*
Nature : "Telomerase
reactivation reverses tissue degeneration in aged telomerase-deficient
mice "
Scientists say they have taken an intriguing first step in the search
for the fountain of youth. Scientists experimented with mice that were
the equivalent of 80-year-old humans and found they were able to
reverse the aging process.
Scientists in Boston have made an astounding discovery, taking aging
mice and turning them young again, like tiny little Benjamin Buttons.
Just like the title character in the Hollywood film version of "The
Curious Case of Benjamin Button," the mice appeared to not only stop
aging but grow younger.
Molecular biologist Dr. Ronald DePinho at Harvard Medical School in
Boston was able to pull off the feat by playing with "telomeres" -- the
protective DNA caps on the ends of our chromosomes.
The caps, which have long been implicated in aging, prevent our
chromosomes from "fraying" and the genes inside them from "unravelling."
Scientists have long known that a little bit of our telomeres erodes
each time our cells divide. Previous research has shown that people
with longer telomeres tend to live longer, whereas those with shorter
telomeres suffer more from age-related diseases, such as Alzheimer's.
A few years ago, DePinho and his research team devised a way to
engineer mice so that they lacked a working copy of the gene that
regulates the production of telomerase, which is an enzyme that
strengthens telomeres and whose production declines over time.
Instead of dying at three years old, the genetically engineered mice
died at about six months. By the time they died, they had become
infertile, their coat hair had turned grey and they had developed
age-related conditions such as osteoporosis.
DePinho wondered whether he could reverse the aging in the mice if they
suddenly began making telomerase again.
So he took a group of engineered mice and added back the telomerase
gene, but left it inactive. His team then allowed the mice to age for
six months, until they were the equivalent of 80-year-old humans. They
then gave the mice a drug that "switched on" the telomerase gene.
One month later, not only did the new production of telomerase stop the
aging process in the mice, it appeared to actually undo the premature
aging so that the mice became the physiological equivalent of young
adults.
Even DePinho was surprised at how effective the experiment was.
"We expected to see a slowing or a stabilization of aging. Instead,
what we found was a dramatic reversal in aging," he told CTV.
"The shrunken brains increased, new neurons were formed, the coat hair
was restored to a new sheen."
DePinho notes that the treated mice went on to have a normal lifespan.
They were simply healthier and biologically younger.
DePinto and his colleagues stress that the study was a
"proof-of-concept" experiment, designed to show that changes to
telomerase can affect aging. There are still many questions to answer
before an experiment can be tried on humans.
For example, some research has shown that telomerase seems to help
cancer tumours grow faster. DePinho says his team didn't observe any
cancers in the mice, but then the telomerase was activated for only one
month.
"This teaches us something fundamental about aging: that aged tissue --
even very aged tissue -- retains the ability to rejuvenate itself," he
said.
DePinho says it's possible the method could be used to treat people
with rare genetic premature aging syndromes. Whether the technique
could help reverse normal aging still remains to be seen. Still, he
says the findings were worth sharing and appear in the journal Nature.
"The results were so dramatic that we wanted to get them out to the
research community as soon as possible so we could inspire the research
community to move forward on these findings," DePinho said.
PATENTS
www.espacenet.com/Advanced Search
US
6767719
Protein and peptide fragments from
mouse telomerase reverse transcriptase
Inventor: MORIN GREGG B [CA] ;
ALLSOPP RICHARD
Abstract --- This invention provides
for murine telomerase reverse transcriptase (mTERT) enzyme proteins and
nucleic acids, including methods for isolating and expressing these
nucleic acids and proteins, which have application to the control of
cell proliferation and aging, including the control of age-related
diseases, such as cancer.
Description
[0002] This application is a continuation-in-part of and claims the
priority benefit of U.S. patent application Ser. No. 08/979,742, filed
Nov. 26, 1997, now abandoned.
[0003] Incorporated herein by reference in their entirety and for all
purposes are the following: U.S. patent application Ser. Nos.
08/979,742; 08/974,549; and 08/974,584; PCT Applications PCT/US97/17618
and PCT/US97/17885; and U.S. patent application Ser. Nos. 08/915,503,
08/912,951, 08/911,312, 08/854,050, 08/851,843, 08/846,017, 08/844,419,
and 08/724,643.
[0004] This invention was made with United States Government support
under Grant No. HD/CA 34880, awarded by the National Institutes of
Health. The United States Government has certain rights in the
invention.
FIELD OF THE INVENTION
[0005] The subject matter of this application provides novel
recombinant telomerase enzyme genes and proteins and relates to the
cloning and characterization of the catalytic protein component of
mouse telomerase enzyme, referred to as mouse telomerase reverse
transcriptase ("mTERT").
[0006] This invention pertains generally to cell proliferation and
aging, including the fields of age-related diseases, such as cancer and
cell biology. In particular, this invention pertains to the discovery
of a novel mTERT enzyme proteins and nucleic acids, and methods for
isolating and expressing by recombinant means these nucleic acids and
proteins. The invention provides antibodies specifically reactive with
mTERT. The invention also pertains to methods of screening for novel
mTERT activity modulators. The invention also includes means of
mortalizing cells, creating indefinitely proliferating cells and
immortalizing cells, including normal, diploid cells, using the novel
reagents, proteins, nucleic acids, enzymes and methods of the invention.
BACKGROUND OF THE INVENTION
[0007] The following discussion is intended to provide general
information regarding the field of the present invention. The citation
of various references is not to be construed as an admission of prior
invention.
[0008] Telomeres, the protein-DNA structures physically located on the
ends of chromosomes in eukaryotic organisms, are required for
chromosome stability and are involved in chromosomal organization
within the nucleus (Zakian (1995) Science 270:1601, Blackburn (1978) J.
Mol. Biol., 120:33, Oka (1980) Gene 10:301, Klobutcher (1981) Proc.
Natl. Acad. Sci. USA 78:3015). Telomeres are believed to be essential
in most eukaryotes, as they allow cells to distinguish intact from
broken chromosomes, protect chromosomes from degradation, and act as
substrates for replication. Telomere loss, i.e., inability to maintain
telomere structure, is associated with normal human cellular
development, including cell aging and cellular senescence. Telomere
gain, i.e., the ability to maintain telomere structure in cells, is
associated with chromosomal changes and cancer.
[0009] Telomeres are generally replicated in a complex, cell cycle and
developmentally regulated manner by a "ribonucleoprotein telomerase
enzyme complex." The telomerase reverse transcriptase enzyme is a
telomere-specific RNA-dependent DNA polymerase comprising a telomerase
reverse transcriptase (TERT) protein and an RNA component. Telomerase
enzyme uses its RNA component to specify the addition of telomeric DNA
repeat sequences to chromosomal ends (U.S. Pat. No. 5,583,016;
Villeponteau (1996) Cell and Develop. Biol. 7:15-21). In addition to
the template RNA component, other proteins have been found to be
associated with TRT. For example, telomerase-associated proteins called
p80 and p95 were found in Tetrahymena (Collins (1995) Cell 81:677).
Homologs of the p80 protein have been found in humans, rats and mice.
Neither enzymatic activity nor amino acid motifs typically associated
with RNA-dependent DNA polymerases have been found to be associated
with these proteins (Harrington (1997) Science 275:973-977). In
contrast, mutational analysis and reconstitution in vitro have shown
the TERT proteins contain the catalytic moieties of telomerase (Lingner
(1997) Science 276:561-567; Weinrich (1997) Nature Genetics
17:498-502). Various structural proteins that interact with telomeric
DNA that are distinct from the protein components of TRT have also been
described. In mammals, most of the simple repeated telomeric DNA is
packaged in closely spaced nucleosomes (Makarov (1993) Cell 73:775,
Tommerup (1994) Mol. Cell. Biol. 14:5777). However, the telomeric
repeats located at the very ends of the human chromosomes appear to be
in a non-nucleosomal structure that has been termed the telosome.
[0010] Telomeric DNA can consist of a variety of different structures.
Typically, telomeres are tandem arrays of very simple sequences, such
as simple repetitive sequences rich in G residues, in the strand that
runs 5' to 3' toward the chromosomal end. In humans, the telomere
repeat sequence is 5'-TTAGGG-3' (SEQ ID NO:7). In contrast, telomeric
DNA in Tetrahymena is comprised of repeats of the sequence T2G4, while
in Oxytricha, the repeat sequence is T4G4 (Zakian (1995) Science
270:1601; Lingner (1994) Genes Develop. 8:1984). Heterogenous telomeric
sequences have been reported in some organisms, such as the repeat
sequence TG1-3 in Saccharomyces. The repeated telomeric sequence in
other organisms is much longer, such as the 25 base pair repeat
sequence of Kluyveromyces lactis. Furthermore, telomeric structure can
be completely different in other organisms. For example, the telomeres
of Drosophila are comprised of a transposable element (Biessman (1990)
Cell 61:663, Sheen (1994) Proc. Natl. Acad. Sci. USA 91:12510).
[0011] In most organisms, the size of the telomere fluctuates. For
example, the amount of telomeric DNA at individual yeast telomeres in a
wild-type strain may range from approximately 200 to 400 bp, with this
amount of DNA increasing and decreasing stochastically (Shampay (1988)
Proc. Natl. Acad. Sci. USA 85:534). Heterogeneity and spontaneous
changes in telomere length may reflect a complex balance between the
processes involved in degradation and lengthening of telomeric tracts.
In addition, genetic, nutritional and other factors may cause increases
or decreases in telomeric length (Lustig (1986) Proc. Natl. Acad. Sci.
USA 83:1398, Sandell (1994) Cell 91:12061).
[0012] Telomeres are not maintained via conventional replicative
processes. Complete replication of the ends of linear eukaryotic
chromosomes presents special problems for conventional methods of DNA
replication. Conventional DNA polymerases cannot begin DNA synthesis de
novo; rather, they require RNA primers that are later removed during
replication. In the case of telomeres, removal of the RNA primer from
the lagging-strand end would necessarily leave a 5'-terminal gap,
resulting in the loss of sequence from the leading strand if the
daughter telomere was subsequently blunt-ended (Watson, (1972) Nature
New Biol. 239:197, Olovnikov (1973) J. Theor. Biol., 41:181).
[0013] While conventional DNA polymerases cannot accurately reproduce
chromosomal DNA ends, specialized factors exist to ensure their
complete replication. The telomerase enzyme is a key component in this
process. In vivo, telomerase enzyme is assembled as a ribonucleoprotein
(RNP) enzyme complex. It is an RNA-dependent DNA polymerase that uses a
portion of its internal RNA moiety as a template for telomere repeat
DNA synthesis (Yu (1990) Nature 344:126; Singer (1994) Science 266:404;
Autexier (1994) Genes Develop. 8:563; Gilley (1995) Genes Develop.
9:2214; McEachern (1995) Nature 367:403; Blackburn (1992) Ann. Rev.
Biochem. 61:113; Greider (1996) Ann. Rev. Became. 65:337). A
combination of factors, including telomerase processivity, frequency of
action at individual telomeres, and the rate of degradation of
telomeric DNA, contribute to the size of the telomeres (i.e., whether
they are lengthened, shortened, or maintained at a certain size). In
vitro, telomerases may be extremely processive; for example,
Tetrahymena telomerase can add an average of approximately 500 bases to
the G strand primer before dissociation of the enzyme (Greider (1991)
Mol. Cell. Biol., 11:4572).
[0014] Telomere replication is regulated both by developmental and cell
cycle factors. Telomere replication may play a signaling role in the
cell cycle. For example, certain DNA structures or DNA-protein complex
formations may act as a checkpoint to indicate that chromosomal
replication has been completed (Wellinger (1993) Mol. Cell. Biol.
13:4057). Telomere length is also believed to serve as a mitotic clock,
which serves to limit the replication potential of cells in vivo and in
vitro.
[0015] In humans, telomerase activity is not detectable in most somatic
tissues. Cell that express either no or only low amounts of telomerase,
such as somatic cells, undergo progressive telomere shortening with
increasing age (Harley (1990) Nature 345:458, Harley (1994) Cold Spring
Harbor Symp. Quant. Biol. 59:307). Some non-transformed, non-immortal
cells have detectable telomerase activity. Germline cells express
telomerase as required to maintain telomeric structure of chromosomes
passed from generation to generation (Greider, (1996) Annu. Rev.
Became. 65:337). Low levels of telomerase activity have been detected
in activated human B and T lymphocytes and hematopoietic progenitor
cells (Keiko (1995) J. Immunol. 155:3711; Igarshi (1997) Blood
89:1299-1307; Igarashi (1996) Biochem. Biophys. Res. Commun. 219:649;
Norrback (1996) Blood 88:222).
[0016] Immortalized cells, such as most cancer cells, express
significantly higher levels of telomerase, allowing for stabilization
of telomeric structure. Telomerase activity has been detected in about
85% of biopsies from more than 950 primary human tumors (Kim (1994)
Science 266:2011; Hiyama (1995) Nature Med. 1:249-257; Counter (1992)
EMBO J. 11:192). Telomerase activity has been detected in many cancers
(Wellinger (1993) supra; Autexier (1996) Trends Biochem. Sci. 21:387).
However, even in telomerase-positive cells, such as most cancer cells,
the levels of telomerase are very low relative to housekeeping and
structural proteins.
[0017] Because telomerase is expressed (albeit in low levels) in most
human cancer cells and is negligibly expressed in other cell types, it
is the only true pan-cancer cell marker identified to date. Thus, there
exists a great need for inhibitors of telomerase activity, which would
be ideal therapeutic compositions in the treatment of cancer or
uncontrolled cell growth. Furthermore, loss of or inhibition of
telomerase activity is associated with cellular senescence and may lead
to cell death. Therefore, there exists a great need for methods and
compositions capable of promoting or reconstituting telomerase activity
which would be useful in treating age-related disease and anti-aging
pharmaceuticals. The present invention fulfills these and other needs.
SUMMARY OF THE INVENTION
[0018] This invention has for the first time provided the
identification, cloning and characterization of mouse telomerase
reverse transcriptase (mTERT) proteins and nucleic acids. Mouse
telomerase enzymes, including associated nucleic acids and other
polypeptides, are further provided. Also, the invention provides novel
reagents and methods complementing this significant achievement.
[0019] The invention provides for an isolated or recombinant nucleic
acid encoding an mTERT, the protein defined as having a calculated
molecular weight of between 50 and 150 kDa, and specifically binding to
an antibody raised against the protein of SEQ ID NO:2, or a subsequence
thereof, or having at least 60% amino acid sequence identity to an
mTERT protein comprising SEQ ID NO:2. In one embodiment, the calculated
molecular weight of the encoded mTERT protein is about 127 kDa. In
further embodiments, the encoded protein has at least 80% amino acid
sequence identity to a protein comprising SEQ ID NO:2, or, the encoded
protein comprises SEQ ID NO:2.
[0020] In alternative embodiments, the invention provides for an
isolated or recombinant nucleic acid which specifically hybridizes to
SEQ ID NO:1 under stringent conditions, an isolated nucleic acid
encoding a protein which specifically binds to an antibody directed
against a protein comprising SEQ ID NO:2, and an isolated nucleic acid
comprising either 10 to 15 or more nucleotides identical or exactly
complementary to SEQ ID NO:1 or a nucleotide sequence encoding at least
about five contiguous amino acids of an mTERT, wherein the TERT has an
amino acid sequence as set forth in SEQ ID NO:2 or conservative
substitutions of said amino acid sequence. In another embodiment, the
invention provides an isolated nucleic acid encoding a fusion protein
comprising an mTERT. The invention also provides a nucleic acid free of
dideoxynucleotides, as well as nucleic acids comprising non-naturally
occurring nucleotides. One embodiment provides for an isolated nucleic
acid comprising a label and a nucleotide sequence of the invention.
[0021] The invention also provides for an isolated or recombinant
peptide encoded by a recombinant or isolated nucleotide sequence
encoding at least about five contiguous amino acids of an mTERT.
[0022] In another embodiment, the invention provides for an isolated or
recombinant mTERT protein where the mTERT has a calculated molecular
weight of about 50 to 150 kDa; and specifically binds to an antibody
raised against a protein comprising SEQ ID NO:2, or subsequence
thereof, or has 60% amino acid sequence identity to a protein
comprising SEQ ID NO:2. The isolated or recombinant mTERT protein can
have a calculated molecular weight of about 127 kDa, or the protein can
comprise SEQ ID NO:2. In an alternative embodiments, the isolated or
recombinant mTERT protein is encoded by a nucleic acid molecule which
specifically hybridizes to SEQ ID NO:1; and, the isolated or
recombinant mTERT protein, or subsequence thereof, can further comprise
a fusion protein.
[0023] The invention provides for an isolated or recombinant antibody
specifically immunoreactive under immunologically reactive conditions
to an mTERT protein; the mTERT protein can comprise the sequence as set
forth in SEQ ID NO:2. The invention also provides for an isolated or
recombinant antibody, specifically immunoreactive under immunologically
reactive conditions, to an mTERT protein encoded by the nucleic acid of
claim 1; the nucleic acid can comprise the sequence as set forth in SEQ
ID NO:1. The invention further provides for an isolated or recombinant
mTERT protein which specifically binds to the anti-mTERT antibodies of
the invention.
[0024] Alternative embodiments provide for a transfected cell
comprising a heterologous gene encoding a mTERT protein or subsequence
thereof; a transfected cell into which an exogenous nucleic acid
sequence has been introduced, where the nucleic acid specifically
hybridizes under stringent conditions to SEQ ID NO:1 or a nucleic acid
of the invention as described herein, and the cell expresses the
exogenous nucleic acid as an mTERT protein; and a transfected cell
where the transfected cell is a karotypically normal diploid cell.
[0025] The invention also provides for an organism into which an
exogenous nucleic acid sequence has been introduced, the nucleic acid
specifically hybridizing under stringent conditions to a nucleic acid
with a sequence as set forth in SEQ ID NO:1, or a nucleic acid of the
invention as described herein, and the organism expresses the exogenous
nucleic acid as a mouse TERT protein. The organism can express an
exogenous nucleic acid comprising a nucleic acid of the invention.
Alternatively, the organism expresses and translates an exogenous
nucleic acid sequence into a mouse TERT protein, which can be expressed
externally from the organism. The organism can be an insect, as a
Spodoptera sp., Trichoplusia sp. or a Lymantria sp. The insect can
specifically be a Spodoptera frugiperda, Trichoplusia ni or a Lymantria
dispar. The organism can be a plant, a fungus or a yeast. If it is a
yeast, the organism can be a Pichia sp., Hansenula sp., Torulopsis sp.,
Saccharomyces sp., or a Candida sp. The yeast can specifically be a
Pichia pastoris, Hansenula polymorpha, Torulopsis holmil, Saccharomyces
fragilis, Saccharomyces cerevisiae, Saccharomyces lactis, or a Candida
pseudotropicalis. The organism can be a bacterium, such as Escherichia
coli, Streptococcus cremoris, Streptococcus lactis, Streptococcus
thermophilus, Leuconostoc citrovorum, Leuconostoc mesenteroides,
Lactobacillus acidophilus, Lactobacillus lactis, Bifidobacterium
bifidum, Bifidobacteriu breve, or a Bifidobacterium longum.
[0026] The invention also provides for an expression vector comprising
a nucleic acid sequence which specifically hybridizes under stringent
conditions to an mTERT encoding nucleic acid; the nucleic acid can have
a sequence as set forth in SEQ ID NO:1.
[0027] The invention also provides for a transfected cell comprising a
recombinant mTERT, wherein said cell is comprised in a transgenic
non-human animal. The invention also provides for a transgenic animal
which lacks a functional mTERT due to its being "knocked out" using
recombinant methods and reagents of the invention. Such mTERT knockouts
mice are especially useful in studying the effect of telomerase and in
testing anti-cancer telomerase inhibitors, i.e., in mice comprising
human tumor xenografts.
[0028] In one embodiment, the invention provides for a transgenic cell
or non-human animal, and progeny thereof, wherein said animal comprises
an endogenous mTERT gene which has been mutated by recombinant means
with a nucleic acid comprising a subsequence of a nucleic acid encoding
an mTERT or complementary to an mTERT. The transgenic cell or non-human
animal can be deficient in at least one mTERT or telomerase enzyme
activity, or completely lack all mTERT or telomerase enzyme activity.
The transgenic cell or non-human animal can comprise an mTERT with a
deficiency in activity which is a result of a mutated gene encoding an
mTERT having a reduced level of a telomerase enzyme activity compared
to a wild-type telomerase enzyme activity. The transgenic cell or
non-human animal can contain a mutated mTERT gene comprising one or
more mutations selected from the group consisting of a missense
mutation, a substitution, a nonsense mutation, an insertion, or a
deletion. The transgenic cell or non-human animal can be a mouse, i.e.,
of the family Muridae. In particular, M. spretus or M. musculus spp.
are provided. The transgenic non-human animal can further comprise a
human telomerase reverse transcriptase.
[0029] The invention further provides for a kit for the detection of a
mouse TERT gene or polypeptide, the kit comprising a container
containing a molecule which can be a TERT nucleic acid or subsequence
thereof, a TERT polypeptide or subsequence thereof, or an anti-TERT
antibody.
[0030] The invention also provides a method of determining whether a
test compound is a modulator of mTERT or telomerase enzyme activity,
the method comprising the steps of: providing a mouse TERT composition,
contacting the TERT with the test compound and measuring the activity
of the TERT, where a change in TERT activity in the presence of the
test compound is an indicator of whether the test compound modulates
mouse TERT or telomerase enzyme activity.
[0031] In a further embodiment, the method is carried out in a buffered
aqueous solution comprising a template polynucleotide, an mTERT, a
buffered aqueous solution compatible with telomerase enzyme activity,
and sufficient additional nucleotide species necessary for
telomerase-catalyzed polymerization of a DNA polynucleotide
complementary to said template polynucleotide. This method can be
carried out in a cell-free extract, an organism or a transgenic
organism. In alternative embodiments of this method: the DNA is a
telomere or comprises a telomeric sequence; the template polynucleotide
is a mouse telomerase RNA (mTR, or mouse telomerase related component,
or mTERC) or comprises an mTERC subsequence; the activity of the
telomerase is measured by monitoring incorporation of a nucleotide
label into DNA; the activity of the telomerase enzyme is measured by
monitoring the change in rate of incorporation of nucleotides into the
DNA; the activity of the telomerase enzyme can also be measured by
monitoring the accumulation or loss of nucleotides into the DNA; the
activity of the telomerase enzyme and mTERT can be further measured by
monitoring the loss of the ability to bind to a telomerase-associated
protein; the activity of the telomerase enzyme and mTERT is measured by
monitoring the loss of the ability to bind to a nucleic acid; and, the
activity of the mTERT is measured by monitoring the loss of the ability
to bind to a chromosome.
[0032] The invention also includes a method where the test compound
produces a statistically significant decrease in the activity of mTERT
as compared to the relative amount of incorporated label in a parallel
reaction lacking the agent, thereby determining that the agent is a
telomerase enzyme or mTERT inhibitor or activator. The method can be
used to determine if there is a change in telomerase enzyme or TERT
activity using, e.g., a TRAP assay or using a quantitative polymerase
chain reaction assay. The method can determine a change in telomerase
enzyme and mTERT activity by measuring the accumulation or loss of
telomere structure.
[0033] The invention provides for isolated and recombinant murine
proteins and nucleic acids that include murine (mTERT) specific motifs
(see FIGS. 4 and 5) and TERT specific "motifs." These motifs effect
common telomerase structure and function and uniquely define members of
the mTERT species of the invention. Novel reagents of the invention
corresponding to these motif regions can be used in methods of the
invention to generate unique murine peptides and nucleic acids,
including complementary and antisense hybridization probes and primers,
to identify additional mTERT, including mTERT isoforms, homologues and
alleles.
[0034] Two mTERT proteins are considered to have a statistically
significant sequence identity, i.e., having significant homology, at
the amino acid level in a conserved region of the TERT protein, such as
the motifs described above and in FIGS. 4, and 5, if, after adjusting
for deletions, additions and the like, the conserved regions have about
20% to 30% sequence identity, as can be deduced or derived from FIGS. 4
or 5. However, this sequence identity can be higher, e.g., as high as
about 40% to 50% or higher, if, e.g. the conserved region of comparison
is shorter, i.e., a region of about 5 to about 10 consecutive amino
acids. Furthermore, the skilled artisan can deduce or derive additional
mTERT motifs, modifications of these mTERT motifs, and variations in
the amount of sequence identity in a particular mTERT motif to
determine whether a polypeptide or nucleic acid is a member of the
mTERT species of the invention, and the like, by reference to the
teachings and sequences of the invention, particularly including FIGS.
4 and 5.
[0035] A further understanding of the nature and advantages of the
present invention may be realized by reference to the remaining
portions of the specification, the figures and claims.
BRIEF DESCRIPTION OF THE FIGURES
[0036] FIG. 1 shows the
complete sequencing of the mouse TERT cDNA (SEQ ID NO:1).
[0037] FIG. 2 shows the deduced
mTERT translation product (SEQ ID NO:2).
[0038] FIG. 3 shows the
alignment of mTERT (SEQ ID NO:2) with hTERT (SEQ ID NO:3). Positions of
motifs are also indicated. Motifs 2 and D are underlined to help
distinguish them from motifs 1 and C, respectively.
[0039] FIG. 4 shows mTERT
motifs in relation to the sequence conservation between mTERT motifs
and other TERT motifs. Motif alignments from top to bottom: human (SEQ
ID NOS:21-27), mouse (SEQ ID NOS:28-39), Euplotes aediculatus (SEQ ID
NOS:35-42), Saccharomyces cerevisiae (SEQ ID NOS:43-50),
Schizosaccharomyces pombe (SEQ ID NOS:51-58). Conserved residues are
indicated in bold. Consensus amino acids (TRT con)=(SEQ ID NOS:59-61).
[0040] FIG. 5 shows the murine,
or Mus, specific TERT motif (specifically, Motif T, Motif 1, Motif 2,
Motif A, Motif B', Motif C, Motif D, and Motif E) sequences of the
invention (SEQ ID NOS:78-80, 65, and 70, respectively) in relation to
other TERT amino acid motifs, (hum=human specific TRT motif=SEQ ID
NOS:71-73, 65, 74-77 and 70, respectively; gen=general TRT motif=SEQ ID
NOS:62-70, respectively)
[0041] FIG. 6 shows a
preliminary sequence of the genomic promoter region of mTERT (SEQ ID
NO:4).
[0042] FIG. 7 shows a schematic
of mTERT genomic DNA from the lambda phage genomic insert, including
relevant restriction enzyme cleavage sites and fragment sizes.
[0043] FIG. 8 shows a sequence
of the genomic promoter region of mTERT (SEQ ID NO:5).
[0044] FIG. 9 presents a
schematic illustration of the mouse gene "knockout" targeting construct
pmTERTKO.
DETAILED DESCRIPTION OF THE INVENTION
[0045] This invention relates to the cloning and characterization of
the mouse telomerase reverse transcriptase (mTERT) gene and provides
isolated and recombinant mTERT proteins and nucleic acids. The
invention further includes isolated and recombinant mouse telomerase
enzymes and related methods.
[0046] The present invention provides an isolated (from synthetic or
natural sources) or recombinant mTERT. In other embodiments, the
invention provides for isolated and recombinant mTERT isoforms,
homologues and alleles, and methods for identifying such mTERT species.
In one embodiment, the mTERT is a protein of about 127 kd, having the
sequence of SEQ ID NO:2, encoded by the cDNA depicted by SEQ ID NO:1.
[0047] The invention also provides for an isolated or recombinant mouse
telomerase enzyme complex comprising at least one mTERT and a
telomerase-associated nucleic acid moiety for use as a template for DNA
synthesis. The telomerase-associated nucleic acid moiety can be derived
from or based on such nucleic acids found in mice (mTERC) or humans
(hTERC). In one embodiment, the telomerase enzyme complex is comprised
of components of mouse origin, including mTERT encoded by the cDNA of
SEQ ID NO:1, a mouse telomerase-associated RNA (mTERC) moiety. In
another embodiment, the telomerase enzyme complex is comprised of
components of mouse and human origin, including mTERT encoded by the
cDNA of SEQ ID NO:1 and an hTERC moiety. The mouse telomerase
enzyme-associated RNA component (mTERC) has been cloned and
characterized, see U.S. Ser. No. 08/782,787, filed 10 Feb. 1997; U.S.
Ser. No. 08/670,516, filed 27 Jun. 1996; and U.S. Ser. No. 08/485,778,
filed 7 Jun. 1995. In addition, hTERC (hTR) knockout mice have been
constructed, see U.S. Ser. No. 08/623,166, filed 28 Mar. 1996. hTERC
has been cloned and characterized, see PCT Publication Nos. 96/01835
and 96/40868 and U.S. Pat. No. 5,583,016.
[0048] In alternative embodiments the telomerase can include any number
of enzyme complex-associated proteins, such as co-purifying proteins
and other proteins that regulate enzyme activity.
[0049] The present invention provides a number of different methods for
expressing and isolating mTERT, telomerase enzyme and
telomerase-associated compounds that can be employed, in one or more
aspects, as reagents and are useful in methodologies as described
herein. The novel reagents and methods of the invention provide for
mice lacking in full or partial mTERT activity, i.e., mTERT "knockout"
mice, and methods for making such mice.
[0050] The telomerase-associated protein can be, for example, the mouse
homologue of the Tetrahymena p80 protein, described in Harrington
(1997) Science 275:973. While some telomerase-associated proteins are
known, the present invention provides methods and reagents for
identifying additional telomerase enzyme-associated proteins and other
compounds and assembling (i.e, "reconstituting") them with mTERT. Such
telomerase enzyme-associated proteins can be prepared in accordance
with, e.g., U.S. Ser. No. 08/883,377 and PCT application No. 97/06012,
both filed Apr. 4, 1997; and PCT application No. 96/14679, U.S. Ser.
No. 08/710,249 and 08/713,922, all filed Sep. 13, 1996. The Tetrahymena
p80 and p95 putative telomerase proteins are described in PCT
publication No. 96/19580.
[0051] The invention, providing for mTERT isoforms, homologues and
alleles, describes structural features common to the mTERT species of
the invention in the form of structural motifs, see FIGS. 4 and 5.
These motifs can effect common mTERT and telomerase enzyme functions.
Sequence analysis of mTERT shows that it contains murine-specific amino
acid regions, i.e., "motifs," common to other mTERT proteins, as
illustrated in FIG. 5.
[0052] Novel reagents of the invention corresponding to these motif
regions can be used in methods of the invention to generate antibodies
and to identify additional mTERT isoforms, homologues and alleles. The
invention provides oligonucleotides corresponding to these motif
regions, including restriction enzyme fragments and amplification
products generated from an mTERT. Oligonucleotides corresponding to
motifs can also be synthesized in vitro. These oligonucleotides can
also be used as PCR amplification primers or hybridization probes to
identify and isolate additional mouse isoforms, homologues and alleles.
These oligonucleotides can also be used as primers to amplify
additional mTERT species, using techniques such as RACE, as described
below.
[0053] The invention further provides for an isolated, purified or
recombinant mouse telomerase enzyme complex capable of replicating
telomeric DNA or any sequence determined by a telomerase
enzyme-associated nucleic acid component. The telomerase enzyme complex
of the invention can comprise components that are purified or isolated
from a natural or synthetic source, a recombinantly manufactured.
[0054] The mTERT of the complex can be modified to delete the full or a
"partial activity" of the TERT or enzyme complex, as described below.
[0055] Telomerase reverse transcriptase enzymes and mTERT are very rare
in nature, and few successful attempts have been made to purify the
enzyme complex; see, as examples of such successful purification, U.S.
Ser. No. 08/510,736, filed Aug. 4, 1995, and U.S. Ser. No. 08/833,377,
and PCT application No. 97/06012, both filed Apr. 4, 1997. The
aforementioned patent applications provide useful methodologies and
reagents that can be applied to the methods and reagents of the present
invention. The present invention provides a variety of methods and
reagents for creating the most pure mouse telomerase enzyme and mTERT
preparations ever made, including methods for making recombinant
telomerase enzyme and mTERT in abundant levels in recombinant host
cells, methods for producing telomerase enzyme and mTERT synthetically
and in cell-free translation systems. The invention provides methods
for isolating recombinant or native telomerase enzyme, mTERT and
telomerase components by reacting the telomerase or mTERT with an
anti-telomerase antibody of the invention.
[0056] Also provided are methods and compositions for the expression of
the mouse telomerase enzymes and mTERTs of the invention. In
alternative embodiments, the compositions of the invention are
expressed as fusion proteins comprising exogenous sequences to aid in
cell targeting, purification, expression and/or detection of mTERT and
telomerase enzyme. The recombinant telomerase enzyme, mTERTs and
telomerase-associated compositions of the invention can be
independently or co-expressed in any system, including bacteria, yeast,
fungi, insect or mammalian cells or the whole organism. The telomerase
enzymes and mTERTs of the invention can also be expressed ex vivo, or
in vivo, e.g., as in transgenic non-human animals.
[0057] The invention also provides for methods of reconstituting
telomerase enzyme and mTERT activity, including fill and partial
activity, in vitro and in vivo, using the purified mTERT of the
invention, with or without further incorporation of its RNA moiety or
telomerase-associated components. As used herein, the term
reconstitution of a telomerase activity in a cell or animal also
includes inducement, augmentation or replacement of low, lost or
"knocked out" telomerase enzyme or mTERT activity. In one embodiment,
the method can reconstitute "full" telomerase activity, ie., the
ability to synthesize telomere DNA. Alternatively, the reconstitution
can be only for "partial activities," as described in detail below. The
invention include reconstitution of hTERT in such mTERT "knockout"
mice, and the animals and their progeny produced by such
reconstitution. The cloning and characterization of hTERT is described,
e.g., in U.S. Ser. No. 08/854,050, filed May 9, 1997; in U.S. Ser. No.
08/915,503, U.S. Ser. No. 08/912,951, and, U.S. Ser. No. 08/911,312,
all filed Aug. 14, 1997; and in U.S. Ser. No. 08/974,549, and U.S. Ser.
No. 08/974,584, both filed on Nov. 19, 1997.
[0058] The assays of the invention can be used to assess the degree of
purification, identify a new mTERT species, such as an mTERT allele,
homologue, or isoform, or to screen for modulators (antagonists and
agonists) of telomerase-mediated DNA replication. Methods for
identifying modulators of a telomerase enzyme activity have been
described in U.S. Pat. No. 5,645,986; and U.S. Ser. No. 08/151,477,
filed Nov. 12, 1993; and U.S. Ser. No. 08/288,501, filed Aug. 10, 1994,
and the reagents of the invention may be employed in such methods.
Antagonists and agonists of mTERT can be used to modify the activity of
other telomerase enzymes, such as hTERT (hTRT).
[0059] The invention contemplates screening for compositions capable of
modifying the polymerase activity of telomerase enzyme, or a partial
activity, by any means. In various embodiments, the invention includes:
screening for antagonists that bind to mTERT's active site or interfere
with transcription of its RNA moiety, as mTERC; screening for
compositions that inhibit the association of nucleic acid and/or
telomerase-associated compositions, such as the association of mTERC
with mTERT or the association of mTERT with mouse p80-homologue or
other telomerase-associated proteins, or association of mTERT with a
telomere, chromosome, nucleosome or a nucleotide; screening for
compositions that promote the dissociation or promote the association
of the enzyme complex, such as an antibody directed to mTERC or mTERT;
screening for agents that effect the processivity of the enzyme; and
screening for nucleic acids and other compositions that bind to mTERT,
such as a nucleic acid complementary to mTERC. The invention further
contemplates screening for compositions that increase or decrease the
transcription of the mTERT gene and/or translation of the mTERT gene
product. These compositions can be used to modify the transcription or
translation of other TERT genes, such as hTERT.
[0060] Screening for antagonist activity provides for compositions that
decrease telomerase replicative capacity, thereby limiting the
proliferative, replicative potential of indefinitely proliferating
cells, or mortalizing otherwise immortal cells, such as cancer cells.
[0061] Screening for agonist activity or transcriptional or
translational activators provides for compositions that increase the
telomerase enzyme's telomere replicative capacity, or, alternatively, a
partial activity as described herein. Such agonist compositions provide
for methods of creating indefinitely proliferating cells, and
immortalizing or increasing the proliferative capacity of otherwise
normal, untransformed cells, including cells which can express useful
proteins. Such agonists can also provide for methods of controlling
cellular senescence, see co-pending U.S. Ser. Nos. 08/912,951 and
08/915,503.
[0062] The novel telomerase compositions and activity reconstitution
assays of the invention also provide for a novel telomerase repeat
amplification protocol assay (TRAP) and variations of this assay. The
TRAP assay is an amplification-based method for detecting, determining,
and measuring telomerase activity and is described in PCT Publication
Nos. 97/15687 and 95/13381 and U.S. Pat. No. 5,629,154; see also U.S.
Ser. No. 08/632,662, and U.S. Ser. No. 08/631,554, filed 15 Apr. 1996
and 12 Apr. 1996, respectively. See also, Kim (1994) supra. The present
invention provides reagents useful for the TRAP assay as well as new
amplification-based telomerase activity assays for a wide variety of
applications. For example, TRAP assays comprising an mTERT protein or a
telomerase enzyme complex of the invention can be used to screen for
modulators of telomerase activity. Such compositions can also be used
to modulate the activity of other telomerase enzymes, such as hTERT, or
to act as a basis for identification of such human telomerase enzyme
modulators.
[0063] The novel telomerase compositions of the invention can also be
used in telomere length assays. Because of the relationship between
telomerase activity and telomere length, the diagnostic and therapeutic
methods of the invention can be used in conjunction with telomere
length assays. A variety of telomere length assays have been described,
see PCT Patent publication Nos. 93/23572, 95/13382, 95/13383, and
96/41016, and U.S. Ser. No. 08/660,402, filed 6 Jun. 1996; 08/479,916,
filed Jun. 7, 1995; and, 08/475,778 and 08/487,290, both filed Jun. 7,
1995.
[0064] The invention provides a method of screening for telomerase
modulators in animals by reconstituting a telomerase activity, or an
anti-telomerase activity, into an animal, such as a transgenic,
non-human animal. The invention provides for in vivo assays systems
that include mouse "knockout" models in which the endogenous mTERT has
been deleted, altered, or inhibited. The endogenous mTERT can be
deleted, altered, or inhibited in either one or both endogenous mTERT
alleles. One embodiment provides for a telomerase deficient mouse, or
mTERT "knockout" mouse, and its progeny. Other embodiments provide for
"knockout" mice, and their progeny, whose ability to express the
telomerase RNA moiety and/or telomerase-associated proteins has also
been deleted, altered, or modified. In one embodiment, an exogenous
telomerase activity (such as human TERT), or endogenous mouse
telomerase activity, full or partial, wild-type or modified, is
reconstituted in the "knock-out" mouse or increased in an otherwise
normal mouse. In alternative embodiments, endogenous mouse telomerase
enzyme or mTERT activities, full or partial, can remain either in one
or both alleles. The telomerase activity reconstituted in the
"knockout" mouse model can include modified endogenous or exogenous
TERT, e.g., mTERT or hTERT alone, hTERT and hTERC, mTERT and mTERC,
mTERT and hTERC. The invention also provides for transgenic cells and
animals, in addition to mice, where mTERT and/or murine telomerase
activity has been inserted through recombinant methodologies. The
non-human transgenic animals of the invention also provide for methods
of expressing large amounts of fully or partially active telomerase
enzyme and mTERT. Transgenic animals also provide for the construction
of indefinitely proliferating cells and the immortalization of
otherwise normal cells, which can then be used, for example, to express
compositions of interest.
[0065] In one embodiment of the invention, recombinant mTERT is
expressed in normal, diploid mortal cells to provide for indefinitely
proliferating cells, immortalization of cells, or to facilitate
long-term culture or replication of the cells. Telomerase enzyme
complex components, such as nucleic acid telomeric sequence template
molecules (mTERC, for example) or other associated proteins, that are
beneficial for expression or act as modulators of activity, can also be
co-expressed. This invention provides methods to obtain indefinitely
proliferating cells and diploid immortal cells with an otherwise normal
phenotype and karyotype. This aspect of the invention is of enormous
practical and commercial utility; for example, the FDA and public would
value the production of recombinant proteins from normal cells to
minimize concern regarding viral or other contamination of the products
made from such cells as are commonly used today. The present invention
allows one to produce indefinitely proliferating and immortal hybrids
of B lymphocytes and myeloma cells to obtain hybridomas for monoclonal
antibody production. Using the methods of this invention, transfection
of mTERT protein and telomerase enzyme activity into B lymphocytes
allows one to generate indefinitely proliferating cells and immortal
cells for antibody production.
[0066] Another embodiment provides for methods for introducing
recombinant mTERT and/or telomerase associated RNA and other compounds
of the invention into cells to produce a commercially desirable
protein. For example, by the methods of the invention an indefinitely
proliferating and an immortal, yet karyotypically normal, pituitary
cell that makes hormones, such as growth hormone, could be produced for
commercial use. In a variation of this embodiment, a normal cell is
removed from the animal, transformed into an indefinitely proliferating
cell, or immortalized, using the methods and reagents of the invention,
transfected with a gene of interest such that the gene is expressed at
appropriate levels and introduced back into the animal such that the
transfected gene expresses a molecule that impacts the health or other
qualities of the animal.
[0067] Another embodiment of the invention involves a similar method,
but the cell is a "universal donor cell" which has been modified to
delete histocompatibility antigens or modified in some way to prevent
or decrease the possibility of immune rejection. A complication arising
from the re-introduction of these cells into an animal is the
possibility that the cells may lose growth control and change to a
state of uncontrolled cell growth, becoming a cancer, tumor or other
malignancy. The present invention solves this complication by providing
means to express mTERT or other telomerase components conditionally
and/or by providing means for knocking out telomerase enzyme, mTERT or
a telomerase enzyme complex component necessary for activity. Moreover,
even "mortal" cells used in transplantation or for other purposes can
be mortalized by such methods of the invention. Without an active
telomerase, the cells are irreversibly mortal, thus decreasing the
probability of cancerous or malignant transformation after
transplantation or other re-introduction into a host organism. This
would not affect the cell's function, as telomerase enzyme is not
normally active in somatic cells.
[0068] The present invention also provides methods and reagents
relating to cis-acting transcriptional and translational regulatory
elements. Examples of cis-acting transcriptional regulatory elements
include promoters and enhancers of the mTERT gene. Examples of
cis-acting translational regulatory elements include elements that
stabilize mRNA or protect the transcript from degradation. The
identification and isolation of cis- and trans-acting regulatory agents
provide for further methods and reagents for identifying agents that
modulate transcription and translation of mTERT and other telomerase
enzymes and TERTs, such as hTERT. While many aspects of these methods
and reagents are described more fully below, U.S. Ser. No. 08/714,482,
filed Sep. 16, 1996, provides useful information relating to reagents
and screens for the hTERC (hTR) promoter that usefully supplements
understanding of certain embodiments of the present invention relating
to the mTERC promoter and isolated and recombinant molecules comprising
all or part of the mTERT promoter and related methods.
[0069] The present invention also provides novel methods and reagents
for immunizing animals to generate an anti-murine telomerase enzyme and
an anti-mTERT immune response. While these methods and compositions are
fully described below, see also U.S. Ser. No. 08/734,052, filed Oct.
18, 1996, for additional useful information.
1. Nucleic Acids Encoding mTERTs
[0070] This invention for the first time provides the identification,
cloning and characterization of the mTERT gene, related polypeptide,
and telomerase enzyme complexes including, as well as providing novel
reagents including or derived from these new compositions that
complement this significant achievement.
[0071] The invention provides for novel means of expressing mTERT in
vitro, ex vivo, and in vivo, thereby providing a means to increase or
decrease endogenous or exogenous TERT expression and activity. These
novel means of expressing mTERT also provide for in vitro, ex vivo, and
in vivo assays to screen for telomerase activity modulators, including
agonist and antagonists. Screening for agonist and antagonist activity
further provides for compositions that can decrease or increase the
telomerase enzyme and TERT's ability to extend telomeres, i.e.,
telomere replicative capacity. Agonist compositions and methods for
creating indefinitely proliferating cells and immortalizing otherwise
normal, untransformed cells, thereby extending cell life, including
cells which can express useful proteins and other compounds, are also
provided. Such agonists and methods provide a means to control cellular
senescence and so ameliorate the diseases associated with aging and
debilitating conditions.
[0072] Telomerase activity has been identified as an important cancer
marker, one whose levels can predict the outcome or seriousness of
disease, as described in U.S. Pat. Nos. 5,489,508; 5,648,125 and
5,639,613. Antagonist compositions, means for screening for such
compositions and methods for inhibiting mTERT and telomerase enzyme in
continuously proliferating, transformed and immortal cells, thereby
shortening cell life, thus are also provided by the invention.
Antagonists of mTERT can also be antagonists of hTERT.
[0073] In another embodiment, the novel compositions of the invention,
including mTERT-encoding nucleic acids and anti-mTERT antibodies, can
also be used to identify and purify mTERT isoforms, homologues, and
alleles. In an alternative embodiment, mTERT and known telomerase
enzyme complex components are used to identify additional
telomerase-associated components. In one embodiment, the nucleic acids
of the invention are used to reconstitute mTERT activity in vitro, ex
vivo, or in vivo. The nucleic acids of the invention can also be used
modify the activity of mTERT, as for example, the invention provides
antisense nucleotide sequences, telomerase-inhibiting ribozymes,
dominant negative mTERT proteins, and gene therapy vectors encoding the
same.
[0074] The invention also provides for methods and associated reagents
incorporating the nucleic acids of the invention that include or can be
used to identify mTERT-specific cis-acting transcriptional control
elements, such as mTERT promoters, and trans-acting elements that bind
to such sequences.
[0075] The invention can be practiced in conjunction with any method or
protocol known in the art, which are well described in the scientific
and patent literature. Therefore, only a few general techniques will be
described prior to discussing specific methodologies and examples
relative to the novel reagents and methods of the invention.
[0076] a. General Techniques
[0077] The mTERT, telomerase enzyme and telomerase-associated nucleic
acids of this invention, whether RNA, cDNA, genomic DNA, or a hybrid
thereof, or synthetically prepared using non-naturally occurring
reagents, may be isolated from a variety of sources or may be
synthesized in vitro. Nucleic acids coding for the protein compositions
of the invention can be expressed in transgenic animals, transformed
cells, in a cell lysate, or in an isolated, partially purified or a
substantially pure form. Techniques for nucleic acid manipulation of
genes encoding the mTERT species of the invention, such as generating
libraries, subcloning into expression vectors, labeling probes,
sequencing DNA, and DNA hybridization are described generally in
Sambrook, ed., MOLECULAR CLONING: A LABORATORY MANUAL (2ND ED.), Vols.
1-3, Cold Spring Harbor Laboratory, (1989) ("Sambrook"); CURRENT
PROTOCOLS IN MOLECULAR BIOLOGY, Ausubel, ed. John Wiley & Sons,
Inc., New York (1997) ("Ausubel"); LABORATORY TECHNIQUES IN
BIOCHEMISTRY AND MOLECULAR BIOLOGY: HYBRIDIZATION WITH NUCLEIC ACID
PROBES, Part I. Theory and Nucleic Acid Preparation, Tijssen, ed.
Elsevier, N.Y. (1993) ("Tijssen"). Sequencing methods typically can
include dideoxy sequencing (Sequenase, U.S. Biochemical), however,
other kits and methods are available and well known to those of skill
in the art.
[0078] Nucleic acids and proteins are detected and quantified in
accordance with the teachings and methods of the invention described
herein by any of a number of general means well known to those of skill
in the art. These include, for example, analytical biochemical methods
such as spectrophotometry, radiography, electrophoresis, capillary
electrophoresis, high performance liquid chromatography (HPLC), thin
layer chromatography (TLC), and hyperdiffusion chromatography, various
immunological methods, such as fluid or gel precipitin reactions,
immunodiffusion (single or double), immunoelectrophoresis,
radioimmunoassays (RIAs), enzyme-linked immunosorbent assays (ELISAs),
immuno-fluorescent assays, and the like, Southern analysis, Northern
analysis, Dot-blot analysis, gel electrophoresis, RT-PCR, quantitative
PCR, other nucleic acid or target or signal amplification methods,
radiolabeling, scintillation counting, and affinity chromatography, to
name only a few.
[0079] b. Isolation, Synthesis, and
Purification of Nucleic Acids Encoding mTERT
[0080] In another embodiment, the invention provides methods to
identify and isolate mTERT isoforms, homologues, and alleles. The
invention provides a recitation of structural features common to mTERT
species of the invention, ie., motifs which are mTERT specific and
motifs which can be used to identify additional mTERT species (see
FIGS. 4 and 5). The murine, or Mus, specific TERT motif (specifically,
Motif T, Motif 1, Motif 2, Motif A, Motif B', Motif C, Motif D, and
Motif E) sequences of the invention are shown in FIG. 5.
[0081] Typically, TERTs are large, basic, proteins having
telomerase-specific amino acid motifs, some of which are reverse
transcriptase (RT) motifs, as disclosed herein. Because these motifs
are conserved across diverse organisms, additional murine TERT mRNA,
cDNA and genes can be obtained or identified using primers, nucleic
acid probes, and antibodies to one or more of the motif sequences.
[0082] Sequence analysis of mTERT shows that it contains amino acid
regions, or motifs, that identify it as a reverse transcriptase (RT)
enzyme. FIGS. 3, 4, and 5, show the alignment of mTERT with other TERT
proteins. The RT region is in the approximately middle third of the
mTERT mRNA (cDNA, SEQ ID NO:1), is the most structurally conserved
region of mTERT as compared to RTs from other organisms. Thus, in one
embodiment, the nucleic acids comprising this and the other motifs
(described in FIGS. 4 and 5) can be used as probes to identify
additional mTERT species. In an alternative embodiment, primers able to
amplify these motif-encoding regions can directly generate new mTERT
species, or generate nucleic acids to be used as hybridization probes
for such mTERT specie identification. In another embodiment, nucleic
acids comprising regions poorly conserved between TERTs, particularly
hTERT, can be used to identify TERTs closely related to mouse mTERT,
such as those from other rodent species. Alternatively, motif regions
can be excised by restriction enzyme digestion for use as hybridization
probes, as described below. Probes targeting mTERT motifs can also be
produced synthetically.
[0083] The motifs found in TERTs, while similar to those found in other
reverse transcriptases, have particular hallmarks. For example, in
motif C the two aspartic acid residues (DD) that coordinate active site
metal ions (see, Kohlstaedt (1992) Science 256:1783; Jacobo-Molina
(1993) Proc. Natl. Acad. Sci. USA 90:6320; Patel (1995) Biochemistry
34:5351) occur in the context hxDD(F/Y) (SEQ ID NO:85) in the
telomerase RTs compared to (F/Y)xDDh (SEQ ID NO:86) in the other RTs
(where h is a hydrophobic amino acid, and "x" is any amino acid; see
Xiong (1990) EMBO J. 9:3353; Eickbush, in The Evolutionary Biology of
Viruses (S. Morse, Ed., Raven Press, N.Y., p. 121, 1994). Another
systematic change characteristic of the telomerase reverse
transcriptase enzymes occurs in motif E, where WxGx (SEQ ID NO:87) is a
consensus among the telomerase proteins, whereas hLGxxh (SEQ ID NO:88)
is characteristic of other RTs (Xiong, supra; Eickbush supra). This
motif E is called the "primer grip" (Jacobo-Molina (1993) supra, Wohrl
(1997) J. Biol. Chem. 272:17581-17587) and mutations in this region
affect priming in RNA polymerases but not priming in DNA polymerases
(Powell (1997) J. Biol. Chem. 272:13262). In addition, the distance
between motifs A and B' is longer in the TERTs than is typical for
other RTs, which may be accommodated as an insertion within the
"fingers" region of the structure which resembles a right hand (see
Kohlstaedt, supra; Jacobo-Molina, supra; and Patel, supra).
[0084] The T motif ("motif T") is an additional hallmark of TERT
proteins (see FIGS. 3 and 4). The T motif comprises a sequence that can
be described using the formula: W-X12-FFY-X-T-E-X10-11-R-X3-W (SEQ ID
NOS:89 and 90), or, alternatively described using the formula:
Trp-R1-X7-R1-R1-R2-X-Phe-Phe-Tyr-X-Thr-Glu-X8-9R3-R3-Arg-R4-X2-Trp SEQ
ID NOS:91 and 92), where X is any amino acid and the subscript refers
to the number of consecutive residues, R1 is leucine or isoleucine, R2
is glutamine or arginine, R3 is phenylalanine or tyrosine, and R4 is
lysine or histidine.
[0085] The T motif can also be described using the formula:
Trp-R1-X4-h-h-X-h-h-R2-p-Phe-Phe-Tyr-X-Thr-Glu-X-p-X3-p-X2-3-R3-R3-R3-Arg-R4-X2-Trp
(SEQ ID NOS:62 and 63) where X is any amino acid, a subscript refers to
the number of consecutive residues, R1 is leucine or isoleucine, R2 is
glutamine or arginine, R3 is phenylalanine or tyrosine, R4 is lysine or
histidine, h is a hydrophobic amino acid selected from Ala, Leu, Ile,
Val, Pro, Phe, Trp, and Met, and p is a polar amino acid selected from
Gly, Ser, Thr, Tyr, Cys, Asn and Gln.
[0086] Motif 1 can also be described using the formula: L-R-X2-P-K-X3
(SEQ ID NO:93), or, alternatively, h-R-h-I-P-K-X3 (SEQ ID NO:94).
[0087] Motif 2 can also be described using the formula: X-R-X-I-X (SEQ
ID NO:95), or, alternatively (F/L)-R-h-I-X2-h (SEQ ID NO:65).
[0088] Motif A can also be described using the formula:
X4-F-X3-D-X4-Y-D-X2 (SEQ ID NO:96), alternatively
P-X-L-Y-F-h-X-h-D-h-X3-Y-D-X-I (SEQ ID NO:97)
[0089] Motif B' can also be described using the formula:
Y-X4-G-X2-Q-G-X3-S-X8 (SEQ ID NO:98), or, alternatively
Q-X2-G-I-P-Q-G-S-X-L-S-X-h-L (SEQ ID NO:99).
[0090] Motif C can also be described using the formula: X6-D-D-X-L-X3
(SEQ ID NO:100), or, alternatively, L-L-R-F-X-D-D-F-L-L-X-T (SEQ ID
NO:101).
[0091] It will be apparent to one of skill that, provided with the
reagents, and the mTERT sequences disclosed herein for those reagents,
and the methods and guidance provided herein (including specific
methodologies described infra), mTERT genes and proteins can be
obtained, isolated and produced in recombinant form by one of ordinary
skill. For example, primers (e.g., degenerate amplification primers)
are provided that hybridize to gene sequences encoding motifs
characteristic of mTERT species to identify further mTERT isoforms,
homologues, and alleles. One or more primers or degenerate primers that
hybridize (as discussed infra) to sequences encoding the above
described mTERT motifs, or combinations of such motifs or TERT
consensus sequence (as shown in FIGS. 4 and 5), can be prepared based
on the codon usage of the target organism, and used to amplify the
mTERT gene sequence from genomic DNA or cDNA prepared from the target
organism. Use of degenerate primers is well known in the art and
entails sets of primers that hybridize to the set of nucleic acid
sequences that can potentially encode the amino acids of the target
motif, taking into account codon preferences and usage of the target
organism, and by using amplification (e.g., PCR) conditions appropriate
for allowing base mismatches in the annealing steps. Typically two
primers are used; however, single primer (or, in this case, a single
degenerate primer set) amplification systems are well known and may be
used to obtain mTERT encoding nucleic acids.
[0092] The T motif is necessary for at least one of telomerase's
activity, including enzymatic catalysis. The mTERT of the invention and
fragments thereof which include the T motif provide for a preferred
nucleic acid or amino acid sequence or subsequence to be used in
methods of the invention, including, for example, methods for
identifying and isolating mTERT alleles, isoforms, and homologues, or,
as described below, for making dominant negative mutant constructs, see
below.
[0093] The mTERTs of the invention can also be identified, isolated and
expressed using methods of the invention, including: i) computer
searches of murine DNA databases for DNAs containing sequences
conserved with an mTERT specie and having sequence identity with TERT
motifs and mTERT sequences described above, ii) hybridization with a
probe from a known mTERT sequence to mouse mRNA, cDNA or RT DNA
sequence or murine cDNA or genomic libraries, and iii) by PCR or other
signal or target amplification technologies of mouse nucleic acid using
primers complementary to regions highly conserved among different
TERTs, such as the motifs of the invention. Amino acid sequences can be
conserved, but, because of the degeneracy of the genetic code, codon
usage bias, or amino acid changes, the DNA sequences corresponding to
motif regions can be different between organisms. For this reason, one
can employ in the methods nucleotides at the positions in the primers
that are degenerate for a particular amino acid to ensure that one or
more of the different primers can hybridize to an mTERT whose
nucleotide sequence is not completely known. In performing PCR with
such primers, one may take allowances for the degenerate positions
probe by using conditions appropriate for allowing certain base
mismatches to occur in the annealing steps of PCR, i.e., degenerate PCR
conditions. Primers of the invention are used to identify murine mTERT
species encompassed by the invention.
[0094] While methods for isolating total DNA or RNA are well known to
those of skill in the art, e.g., see Tijssen and Sambrook, illustrative
example of methods for identifying, characterizing and isolating mTERT
nucleic acids of the invention are provided below.
[0095] i. Preparation and Screening of
TERT-encoding DNA Libraries
[0096] There are numerous methods for isolating DNA sequences encoding
the mTERT of the invention. For example, mTERT DNA can be identified by
stringent hybridization and isolated from a murine genomic or cDNA
library using oligonucleotide probes, typically labeled, having
sequences complementary to mTERT sequences or subsequences, such as
TERT motifs, as disclosed herein. For example, the mTERT encoded by the
genomic and cDNA nucleic acid whose sequence is set forth in SEQ ID
NO:1, can be used to construct such probes or primers. Such probes can
be used directly in hybridization assays to isolate DNA encoding mTERT
species. Alternatively probes can be designed for use in amplification
techniques such as PCR.
[0097] The invention provides compositions and methods to screen both
genomic and cDNA libraries for mTERT sequences. Screening cDNA
libraries for coding sequences has certain advantages in that no
intronic sequences are usually present. Screening genomic libraries has
an advantage in that upstream and downstream cis-acting transcriptional
regulatory elements can be identified and isolated, as well as introns,
promoters and enhancers which may be beneficial to include in some
expression vectors. Furthermore, in some species, the intronic or
untranscribed mTERT sequences may be the most conserved. Accordingly,
the invention provides for the isolation of mTERT genomic nucleic
acids, including introns, protein-encoding exons, and transcribed and
non-transcribed genomic sequences as additional reagents and means to
identify and screen for mTERT isoforms, alleles and homologues.
[0098] Identification of mTERT cis-acting regulatory elements provides
reagents and means to isolate further mTERT trans-acting regulatory
compounds. Identification of such mTERT regulatory elements provides
the means to design TERT modulating compounds which can be used to up-
or down-regulate TERT transcription, translation, or assembly of a
functional or partially functional (i.e., having "partial activity")
TERT or telomerase enzyme. The invention also provides isolated and
recombinant nucleic acids comprising the mouse genomic promoter region,
as described below, and identified in SEQ ID NO:1.
[0099] To prepare a cDNA library, mRNA is isolated, reverse transcribed
and inserted into vectors in accordance with general procedures well
known in the art. The vectors are transfected into a recombinant host
for propagation, screening and other applications. Methods for making
and screening cDNA libraries are well known, see e.g, Gubler (1983)
Gene 25:263-269; Shepard (1997) Nucleic Acids Res. 25:3183-3185; Davis
(1997) Proc. Natl. Acad. Sci. USA 94:2128-2132; Alphey (1997)
Biotechniques 22:481-484; and Sambrook. To make a genomic library,
total DNA is extracted and purified by well-known methods (see, e.g.,
Sambrook, Ausubel). DNA of appropriate size is produced by known
methods, such as mechanical shearing or enzymatic digestion, to yield
DNA fragments, e.g., of about 12 to 20 kb. The fragments are then
separated, as for example, by gradient centrifugation, or gel
electrophoresis, from undesired sizes. Selected fragments can be
inserted in bacteriophage or other vectors. These vectors and phage can
be packaged in vitro, as described, e.g., in Sambrook. Recombinant
phage can be analyzed by plaque hybridization as described, e.g., in
Benton (1977) Science 196:180; Chen (1997) Methods Mol Biol 62:199-206.
Colony hybridization can be carried out as generally described in the
scientific literature, e.g., as in Grunstein (1975) Proc. Natl. Acad.
Sci. USA 72:3961-3965; Yoshioka (1997) J. Immunol Methods 201:145-155;
Palkova (1996) Biotechniques 21:982.
[0100] DNA encoding an mTERT isoform, homologue, or allele can be
identified in either murine cDNA or genomic libraries by hybridization
with nucleic acid probes of the invention, e.g., probes containing 10
to 20 to 50 or more contiguous nucleotides of SEQ ID NO:1, on Southern
blots. Once identified, these DNA regions are isolated by standard
methods familiar to those of skill in the art. Alternatively, RNA
encoding mTERT protein may be identified by hybridization to nucleic
acid probes in Northern blots or other formats; see, e.g., Sambrook for
general procedures relating to such formats.
[0101] Oligonucleotides for use as probes can be chemically
synthesized, as described below. Synthetic nucleic acids, including
oligonucleotide probes and primers, mTERT coding sequences, antisense,
ribozymes and the like can be prepared by a variety of solution or
solid phase methods. Detailed descriptions of the procedures for solid
phase synthesis of nucleic acids by phosphite-triester,
phosphotriester, and H-phosphonate chemistries are widely available.
For example, the solid phase phosphoramidite triester method of
Beaucage and Carruthers using an automated synthesizer is described in
Itakura, U.S. Pat. No. 4,401,796; Carruthers, U.S. Pat. Nos. 4,458,066
and 4,500,707; Carruthers (1982) Genetic Engineering 4:1-17; see also
Needham-VanDevanter (1984) Nucleic Acids Res. 12:6159-6168; Beigelman
(1995) Nucleic Acids Res 23: 3989-3994; Jones, chapt 2, Atkinson, chapt
3, and Sproat, chapt 4, in OLIGONUCLEOTIDE SYNTHESIS: A PRACTICAL
APPROACH, Gait (ed.), IRL Press, Washington D.C. (1984); Froehler
(1986) Tetrahedron Lett. 27:469-472; Froehler, Nucleic Acids Res.
14:5399-5407 (1986); Sinha, Tetrahedron Lett. 24:5843-5846 (1983); and
Sinha, Nucl. Acids Res. 12:4539-4557 (1984); for synthesis of
fluorescently labeled oligonucleotides and their application in DNA
sequencing, see Markiewicz (1997) Nucleic Acids Res. 25:3672-3680;
Shchepinov (1997) Nucleic Acids Res. 25:4447-4454, describing synthesis
of a phosphoramidite synthon.
[0102] Methods to purify oligonucleotides include, for example, native
acrylamide gel electrophoresis, anion-exchange HPLC, as described in
Pearson (1983) J. Chrom. 255:137-149, and Ausserer (1995) Biotechniques
19:136-139; Arghavani (1995) Anal. Biochem. 231:201-209, using
reversed-phase high-performance liquid chromatography, and the like.
The sequence of the synthetic oligonucleotide can be verified using any
chemical degradation method, e.g., see Maxam (1980) Methods in Enzymol.
65:499-560, Xiao (1996) Antisense Nucleic Acid Drug Dev. 6:247-258; or
for solid-phase chemical degradation procedures, see e.g., Rosenthal
(1987) Nucleic Acids Symp. Ser. 18:249-252; to sequence
phosphorothioate DNA, see Froim (1997) Nucleic Acids Res. 25:4219-4223.
[0103] ii. Amplification of Nucleic
Acids Encoding TERT and Telomerase
[0104] The present invention provides oligonucleotide primers and
probes that can hybridize specifically to nucleic acids having mTERT
protein-encoding cDNA or genomic nucleic acid, such as the mTERT
sequence of SEQ ID NO:1, encoding the polypeptide of SEQ ID NO:2. Such
reagents can be used to identify any species of mTERT protein-encoding
and genomic sequences. mTERT genomic sequences include intronic and
genomic, non-transcribed sequences, promoters, and enhancers which can
also be amplified using the PCR primers of the invention to identify
new mTERT isoforms, alleles and homologues. Illustrative PCR primers
and amplification methods are described below.
[0105] Amplification of mTERT sequences which are conserved amongst
different mTERT species, i.e., consensus or motif mTERT sequences, as
described above, can be used to generate oligonucleotides that are
preferred reagents of the invention. The reagents are used as
hybridization probes to identify and isolate additional mTERT species.
These oligonucleotides can also be used as primers to amplify
additional mTERT species directly, using any amplification technique,
such as, for example RACE, as described below.
[0106] Oligonucleotides can be used to identify and detect additional
mTERT species using a variety of hybridization techniques and
conditions. One of skill in the art will appreciate that, whatever
amplification method is used, if a quantitative result is desired, care
must be taken to use a method that maintains or controls for the
relative frequencies of the amplified nucleic acids. Suitable
amplification methods include, but are not limited to: polymerase chain
reaction, PCR (PCR PROTOCOLS, A GUIDE TO METHODS AND APPLICATIONS, ed.
Innis, Academic Press, N.Y. (1990) and PCR STRATEGIES (1995), ed.
Innis, Academic Press, Inc., N.Y. ("Innis")), ligase chain reaction
(LCR) (Wu (1989) Genomics 4:560; Landegren (1988) Science 241:1077;
Barringer (1990) Gene 89:117); transcription amplification (Kwoh (1989)
Proc. Natl. Acad. Sci. USA 86:1173); self-sustained sequence
replication (Guatelli (1990) Proc. Natl. Acad. Sci. USA, 87:1874); Q
Beta replicase amplification (Smith (1997) J. Clin. Microbiol.
35:1477-1491, automated Q-beta replicase amplification (Burg (1996)
Mol. Cell. Probes 10:257-271); and other RNA polymerase mediated
techniques (e.g., NASBA, Cangene, Mississauga, Ontario); see also
Berger (1987) Methods Enzymol. 152:307-316, Sambrook, and Ausubel, as
well as Mullis (1987) U.S. Pat. Nos. 4,683,195 and 4,683,202; Arnheim
(1990) C&EN 36-47; Lomell (1989) J. Clin. Chem. 35:1826; Van Brunt
(1990) Biotechnology 8:291-294; Wu (1989) Gene 4:560; and Sooknanan
(1995) Biotechnology 13:563-564. Methods for cloning in vitro amplified
nucleic acids are described in Wallace, U.S. Pat. No. 5,426,039.
[0107] The invention provides for amplification and manipulation or
detection of the products from each of the above methods to prepare DNA
encoding mTERT protein or otherwise identical or complementary mTERT
gene sequences. In PCR techniques, oligonucleotide primers
complementary to the two borders of the DNA region to be amplified are
synthesized and used (see, e.g., Innis). PCR can be used in a variety
of protocols to amplify, identify, isolate and manipulate nucleic acids
encoding mTERT. In these protocols, appropriate primers and probes for
identifying and amplifying DNA encoding mTERT polypeptides and
fragments thereof are generated that comprise all or a portion of any
of the DNA sequences listed herein. PCR-amplified sequences can also be
labeled and used as detectable oligonucleotide probes, but such nucleic
acid probes can be generated using any synthetic or other technique
well known in the art.
[0108] The present invention provides RACE-based methods for isolating
mTERT nucleic acids. RACE is another PCR-based approach for DNA
amplification. Briefly, this technique involves using PCR to amplify a
DNA sequence using an introduced random 5' primer and a gene-specific
3' primer (5' RACE) or an introduced random 3' primer and a gene
specific 5' primer (3' RACE). The amplified sequence is then subcloned
into a vector where can be sequenced and manipulated using standard
techniques. The RACE method is well known to those of skill in the art
and kits to perform RACE are commercially available, e.g. Gibco BRL,
Gaithersburg, Md., #18374-058 (5' RACE) or #18373-019 (3' RACE), see
also Lankiewicz (1997) Nucleic Acids Res 25:2037-2038; Frohman (1988)
Proc. Natl. Acad. Sci. USA 85:8998; and Doenecke (1997) Leukemia
11:1787-1792.
[0109] For 5' RACE, a primer, the gene-specific primer, is selected
near the 5' end of the known sequence oriented to extend towards the 5'
end. The primer is used in a primer extension reaction using a reverse
transcriptase and mRNA. After the RNA is optionally removed, the
specifically-primed cDNA is either: 1) "tailed" with deoxynucleotide
triphosphates (dNTP) and dideoxyterminal transferase; then a primer
that is complementary to the tail with a 5' end that provides a unique
PCR site and the first gene-specific primer is used to PCR amplify the
cDNA; subsequent amplifications are usually performed with a
gene-specific primer nested with respect to the first primer, or 2) an
oligonucleotide that provides a unique PCR site is ligated to an end of
the cDNA using RNA ligase; then a primer complimentary to the added
site and the first gene-specific primer is used to PCR amplify the
cDNA, with subsequent amplifications usually performed with a
gene-specific primer nested with respect to the first primer. Amplified
products are then purified, usually by gel electrophoresis, then
sequenced and the sequence examined to determine if the products
contain the additional cDNA sequences desired.
[0110] For 3' RACE, an oligo dT-primer is annealed to the poly-A tails
of an mRNA and then extended by a reverse transcriptase. Usually the
oligo dT primer has a 5' end that provides a unique PCR site. The RNA
is then removed, optionally, or dissociated, and the cDNA is amplified
with a primer to the oligo dT tail and a gene-specific primer near the
3' end of the known sequence (oriented towards the 3' end). Subsequent
amplifications are usually performed with a gene-specific primer nested
with respect to the first primer. Amplified products are then purified,
usually by gel electrophoresis, then sequenced and examined to
determine if the products contain the additional cDNA sequences desired.
[0111] Another useful means of obtaining nucleic acids of the
invention, such as large genomic clones, is to screen BAC or P1 murine
genomic libraries. BACs, bacterial artificial chromosomes, are vectors
that can contain 120+ Kb inserts (for example, see Asakawa (1997) Gene
191:69-79, for a description of the construction and of a human BAC
library. BACs are based on the E. coli F factor plasmid system and are
simple to manipulate and purify in microgram quantities. Because BAC
plasmids are kept at one to two copies per cell, the problems of
rearrangement observed with YACs, which can also be employed in the
present methods, are reduced. For delivery of bacterial artificial
chromosomes into mammalian cells see, e.g., Baker (1997) Nucleic Acids
Res. 25:1950-1956. BAC vectors can include marker genes for luciferase
and green fluorescent protein (GFP). (Baker (1997) Nucleic Acids Res
25:1950-1956). P1 is a bacteriophage that infects E. coli that can
contain 75-100 Kb DNA inserts (Mejia (1997) Genome Res 7:179-186;
Ioannou (1994) Nat Genet 6:84-89), and are screened in much the same
way as lambda libraries.
[0112] iii. Analysis of the mTERT
Species: Isoforms, Alleles, Homologues
[0113] The mTERT-encoding nucleic acid sequences of the invention
include isolated and recombinant nucleic acids relating to mTERT genes
and gene products identified and characterized by analysis of mTERT
sequences. Optimal alignment of sequences for comparison can use any
means to analyze sequence identity (homology) known in the art, e.g.,
by the progressive alignment method of termed "PILEUP" (see below); by
the local homology algorithm of Smith & Waterman, Adv. Appl. Math.
2: 482 (1981); by the homology alignment algorithm of Needleman &
Wunsch, J. Mol. Biol. 48:443 (1970); by the search for similarity
method of Pearson (1988) Proc. Natl. Acad. Sci. USA 85: 2444; by
computerized implementations of these algorithms (GAP, BESTFIT, FASTA,
and TFASTA in the Wisconsin Genetics Software Package, Genetics
Computer Group, 575 Science Dr., Madison, Wis.); ClustalW (CLUSTAL in
the PC/Gene program by Intelligenetics, Mountain View, Calif.,
described by Higgins (1988) Gene, 73: 237-244; Corpet (1988) Nucleic
Acids Res. 16:10881-90; Huang (1992) Computer Applications in the
Biosciences 8:155-65, and Pearson (1994) Methods in Molec. Biol.
24:307-31), TreeAlign, MALIGN, and SAM sequence alignment computer
programs; or, by inspection. See also Morrison (1997) Mol. Biol. Evol.
14:428-441, as an example of the use of PILEUP. PILEUP creates a
multiple sequence alignment from a group of related sequences using
progressive, pairwise alignments. It can also plot a tree showing the
clustering relationships used to create the alignment. PILEUP uses a
simplification of the progressive alignment method of Feng &
Doolittle, J. Mol. Evol. 35:351-360 (1987). The method used is similar
to the method described by Higgins & Sharp (1989) CABIOS 5:
151-153. The program can align up to 300 sequences of a maximum length
of 5,000. The multiple alignment procedure begins with the pairwise
alignment of the two most similar sequences, producing a cluster of two
aligned sequences. This cluster can then be aligned to the next most
related sequence or cluster of aligned sequences. Two clusters of
sequences can be aligned by a simple extension of the pairwise
alignment of two individual sequences. The final alignment is achieved
by a series of progressive, pairwise alignments. The program can also
be used to plot a dendogram or tree representation of clustering
relationships. The program is run by designating specific sequences and
their amino acid or nucleotide coordinates for regions of sequence
comparison. For example, hTERT can be compared to other TERT species
using the following parameters: default gap weight (3.00), default gap
length weight (0.10), and weighted end gaps.
[0114] Another example of algorithm that is suitable for determining
sequence similarity is the BLAST algorithm, which is described in
Altschul (1990) J. Mol. Biol. 215: 403-410. Software for performing
BLAST analyses is publicly available through the National Center for
Biotechnology Information; see also Zhang (1997) Genome Res. 7:649-656
(1997) for the "PowerBLAST" variation. This algorithm involves first
identifying high scoring sequence pairs (HSPs) by identifying short
words of length W in the query sequence that either match or satisfy
some positive-valued threshold score T when aligned with a word of the
same length in a database sequence. T is referred to as the
neighborhood word score threshold (Altschul et al, supra). These
initial neighborhood word hits act as seeds for initiating searches to
find longer HSPs containing them. The word hits are extended in both
directions along each sequence for as far as the cumulative alignment
score can be increased. Extension of the word hits in each direction
are halted when: the cumulative alignment score falls off by the
quantity X from its maximum achieved value; the cumulative score goes
to zero or below, due to the accumulation of one or more
negative-scoring residue alignments; or the end of either sequence is
reached. The BLAST algorithm parameters W, T, and X determine the
sensitivity and speed of the alignment. The BLAST program uses as
defaults a wordlength (W) of 11, the BLOSUM62 scoring matrix (see
Henikoff (1989) Proc. Natl. Acad. Sci. USA 89:10915) alignments (B) of
50, expectation (E) of 10, M=5, N=-4, and a comparison of both strands.
The BLAST algorithm performs a statistical analysis of the similarity
between two sequences (see, e.g., Karlin (1993) Proc. Natl. Acad. Sci.
USA 90: 5873-5787). One measure of similarity provided by the BLAST
algorithm is the smallest sum probability (P(N)), which provides an
indication of the probability by which a match between two nucleotide
or amino acid sequences would occur by chance.
[0115] iv. Sequencing of mTERT DNA
[0116] Sequencing of isolated mTERT-encoding nucleic acid can be used
to identify and characterize new mTERT species. mTERT protein-encoding
sequences can be sequenced as inserts in vectors, as inserts released
and isolated from the vectors or in any of a variety of other forms
(i.e., as amplification products). mTERT-encoding inserts can be
released from the vectors by restriction enzymes or amplified by PCR or
transcribed by a polymerase. For sequencing of the inserts to identify
full length mTERT coding sequences, primers based on the N- or
C-terminus, or based on insertion points in the original phage or other
vector, can be used. Additional primers can be synthesized to provide
overlapping sequences. A variety of nucleic acid sequencing techniques
are well known and described in the scientific and patent literature,
e.g., see Rosenthal (1987) supra; Arlinghaus (1997) Anal. Chem.
69:3747-3753, for use of biosensor chips for sequencing; Healey (1997)
Anal. Biochem. 251:270-279, describing fiberoptic DNA sensor arrays
capable of detecting point mutations; Pastinen (1996) Clin. Chem.
42:1391-1397; Nyren (1993) Anal Biochem. 208:171-175.[0117] v.
Chromosomal Location of mTERT Encoding DNA
[0118] Identification of the location of the chromosomal location of
mTERT coding sequences in different strains of wild-type mice will
provide insights into mechanisms controlling the expression of the
mTERT gene. Identification of the chromosomal location of mTERT in
transgenic and mouse mTERT "knockout" mice also helps evaluate model
systems. To ascertain the chromosomal location of the mTERT gene in a
mouse, the segregation of mTERT in a Jackson Laboratory BSS
interspecific backcross (see Rowe (1994) Mammalian Genome 5:253-274)
was analyzed. Comparison of the allele distribution pattern of the
mTERT locus with those of other loci previously mapped throughout the
genome showed that mTERT cosegregated with D13Mit8 and D13Gor1 (Rowe
(1994) supra, Xu (1996) Mammalian Genome 7:16-19). Comparing the BSS
cross data to information from other linkage crosses in the Mouse
Genome Database (MGD, see www.informatics.jax.org/mgd.html, The Jackson
Laboratory), one finds that mTERT fits the composite mouse chromosome
13 map near MGD offset 40, in proximity to srd5a1, Adcy2, Dat1, and
S1c9a3 genes. The specific region to which mTERT maps defines a
conserved linkage group near the terminus of the short arm of human
chromosome 5, band 15. Similar techniques can be used to map mTERT
inserted into transgenic animals into which mTERT nucleic acid has been
inserted to express murine telomerase as an exogenous entity; or, in
"knockout" mice into which mTERT nucleic acid or a variant has been
inserted to alter or abrogate the expression of endogenous mTERT.
[0119] c. Nucleic Acid Hybridization
Techniques
[0120] The hybridization techniques disclosed herein can be utilized to
identify, isolate and characterize genes and gene products (i.e., mRNA)
encoding mTERT species. A variety of methods for specific DNA and RNA
detection and measurement using nucleic acid hybridization techniques
are known to those of skill in the art. See, e.g., NUCLEIC ACID
HYBRIDIZATION, A PRACTICAL APPROACH, Ed. Hames, B. D. and Higgins, S.
J., IRL Press, 1985; Gall (1989) Proc. Natl. Acad. Sci. USA 63:378; and
Sambrook. The selection of a DNA hybridization format is often
optional. For example, one method for evaluating the presence or
absence of a DNA encoding an mTERT protein in a sample involves a
Southern transfer. Briefly, the nucleic acid sample, such as digested
murine DNA or mRNA, is run on agarose slab or polyacrylamide gel in
buffer and transferred to membranes. Hybridization is carried out using
nucleic acid probes. For the mTERT nucleic acids of this invention, the
nucleic acid probes can comprise nucleic acid sequences conserved
amongst mTERT nucleic acids. Preferably nucleic acid probes are 10 to
20 bases or longer in length, see, e.g., Sambrook for methods of
selecting nucleic acid probe sequences for use in nucleic acid
hybridization. Both quantitative and qualitative determination of the
presence or absence of DNA or RNA encoding mTERT protein can be
performed in accordance with the present methods.
[0121] Similarly, and as but one of many examples, a Northern transfer
can be used for the detection of murine message RNA encoding mTERT
polypeptides. For example, mRNA is isolated from a given cell sample
using an acid guanidinium-phenol-chloroform extraction method. The mRNA
is then electrophoresed to separate the mRNA species and the mRNA is
transferred from the gel to a nitrocellulose membrane. As with the
Southern transfers, probes, labeled probes or PCR amplification
products can be used to identify the presence or absence of telomerase
protein-encoding nucleic acid. The mTERT mRNA of the invention is often
expressed in cells at such low levels that it can be difficult to
detect by Northern blotting, even using the most sensitive assays. This
can be true even with cells that express relatively high levels of
mTERT mRNA, such as indefinitely proliferating, immortal and cancer
cells. The low level of mTERT mRNA, even in mTERT-positive cells, ie.,
cells that express telomerase enzyme activity, such as cancer cells, is
reflected by the low levels of mTERT protein that may be seen in such
cells. Such protein can be detected by the detection methods of the
invention, including immunoblotting (e.g., Western blots).
[0122] Sandwich assays can also be used to detect mTERT species. They
are commercially useful hybridization assays for detecting or isolating
protein or nucleic acid. Such assays utilize a "capture" nucleic
acid or protein that is often covalently immobilized to a solid support
and a labeled "signal" nucleic acid, typically in solution. A clinical
or other sample provides the target nucleic acid or protein. The
"capture" nucleic acid or protein and "signal" nucleic acid or protein
hybridize with or bind to the target nucleic acid or protein to form a
"sandwich" hybridization complex. To be effective, the signal nucleic
acid or protein cannot hybridize or bind substantially with the capture
nucleic acid or protein. Typically, oligonucleotide probes are labeled
signal nucleic acids that are used to detect hybridization.
Complementary probe nucleic acids or signal nucleic acids may be
labeled by any one of several methods typically used to detect the
presence of hybridized polynucleotides. Labels for autoradiography or
autofluorography, such as <3> H, <125> I, <35> S,
<14> C, or <3> P-labeled probes or the like (see definition
of label, above) can be used. Other labels include ligands which bind
to labeled antibodies, fluorophores, chemiluminescent agents, enzymes,
and antibodies which can serve as specific binding pair members for a
labeled ligand.
[0123] Detection of a hybridization complex may require the binding of
a signal generating complex to a duplex of target and probe
polynucleotides or nucleic acids. Typically, such binding occurs
through ligand and anti-ligand interactions as between a
ligand-conjugated probe and an anti-ligand conjugated with a signal,
i.e., antibody-antigen or complementary nucleic acid binding. The label
may also allow indirect detection of the hybridization complex. For
example, where the label is a hapten or antigen, the sample can be
detected by using antibodies. In these systems, a signal is generated
by attaching fluorescent or enzymatic molecules to the antibodies or,
in some cases, by attachment of a radioactive label. The sensitivity of
the hybridization assays may be enhanced through use of a target
nucleic acid or signal amplification system which multiplies the target
nucleic acid or signal being detected. In vitro amplification
techniques suitable for amplifying sequences for use as molecular
probes or for generating nucleic acid fragments for subsequent
subcloning are known, as described above. These systems can be used to
directly identify allelic variations or mutated sequences where the PCR
or LCR primers or other reagents are designed to be extended or ligated
only when a specific sequence is present. Alternatively, the specific
sequences can be generally amplified using, for example, more generic
PCR primers and the amplified target region later probed or sequenced
to identify a specific sequence indicative of the allele or mutation.
[0124] It will be appreciated that nucleic acid hybridization assays
for identification, diagnosis, sequencing, and the like, of mTERT can
also be performed in an array-based format. Arrays involve a
multiplicity of different "probe" or "target" nucleic acids (or other
compounds) that are hybridized against a target nucleic acid. In this
manner a large number of different hybridization reactions can be run
essentially "in parallel". This provides rapid, essentially
simultaneous, evaluation of a wide number of reactants. Methods of
performing hybridization reactions in array based formats are well
known to those of skill in the art, e.g., Jackson (1996) Nature
Biotechnology 14:1685; Chee, Science 274:610 (1995); Pastinen (1997)
Genome Res. 7:606-614, describing minisequencing on oligonucleotide
arrays; and Drobyshev (1997) Gene 188:45-52, for sequence analysis by
hybridization with oligonucleotide microchip.
[0125] An alternative means for determining the level of expression of
a gene encoding a protein is in situ hybridization. In situ
hybridization assays are well known and are generally described in
Angerer (1987) Methods Enzymol 152:649. In an in situ hybridization
assay, cells can be fixed to a solid support, typically a glass slide,
or be free in solution. If DNA is to be probed, the cells are typically
denatured with heat or alkali. The cells are then contacted with a
hybridization solution at a moderate temperature to permit annealing of
labeled probes specific to the nucleic acid sequence encoding the
protein. The probes are typically labeled, i.e., with radioisotopes or
fluorescent reporters. See also U.S. Pat. No. 5,583,016, U.S. Ser. Nos.
08/472,802 and 08/482,115, both filed Jun. 7, 1995; U.S. Ser. No.
08/521,634, filed Aug. 31, 1995; U.S. Ser. No. 08/714,482, filed Sep.
16, 1996; and U.S. Ser. Nos. 08/770,564 and 08/770,565, both filed 20
Dec. 1996; Soder (1997) Oncogene 14:1013-1021, all of which describe in
situ hybridization of hTERC. Another well-known in situ hybridization
technique is the so-called FISH fluorescence in situ hybridization, see
Macechko (1997) J. Histochem. Cytochem. 45:359-363; and Raap (1995)
Hum. Mol. Genet. 4:529-534.
[0126] d. Expression of Recombinant
Telomerase and mTERT
[0127] To create cell-based assay systems to screen for modulators of
mTERT, a variety of cell-based and in vitro systems are provided by the
invention. The invention provides for methods and reagents to express
the novel mouse telomerase enzymes and mTERTs of the invention in any
prokaryotic, eukaryotic, yeast, fungal, plant, insect, human or animal
cell, either alone or co-expressed with a telomerase-associated RNA
moiety and/or other telomerase-associated proteins. The mTERT can be
associated with mTERC or hTERC. The transfected mTERT can be expressed
as an exogenous telomerase in a cell having full or partial endogenous
telomerase enzyme activity. The mTERT can also be mutated or modified
and subsequently transfected and expressed in a mouse cell.
[0128] In one embodiment, the endogenous mTERT can be first
debilitated, or "knocked out" in either one or both alleles before
introducing an exogenous TERT and/or TERC (e.g., altering endogenous
mTERT activity and reconstituting with mTERT and mTERC, mTERT and
hTERC, hTERT and mTERC, or, hTERT and hTERC) and other
telomerase-associated components. The expression of mTERT in cells that
have less than full or completely "knocked out" endogenous telomerase
activity can reconstitute or re-introduce full or partial telomerase
enzyme activity. Other telomerase-associated compositions, such as p80,
can be co-expressed in these cell systems.
[0129] Using these or other in vitro or in vivo cell systems, the
invention provides a means to assay for modulators of telomerase enzyme
expression, including agonist and antagonists of telomerase enzyme and
mTERT activity, transcription and translation of the mTERT gene, and
assembly, processivity and substrate binding of mTERT and telomerase
(see the further discussion of "partial" TERT activity, below). The
invention also provides method for reconstitution of full or partial
telomerase of mTERT activity in vitro.
[0130] Telomerase-encoding nucleic acids of the invention may be
introduced into the genome or into the cytoplasm or nucleus of an
animal or plant cell by a variety of conventional techniques, well
described in the scientific and patent literature. A few selected
illustrative general and specific teaching examples relevant to such
technology are described below.
[0131] i. Cloning, Vectors, and
Transcriptional Control Elements
[0132] The invention provides methods and reagents for expressing the
novel murine telomerase enzyme and mTERT nucleic acids of the invention
and further provides methods and reagents for identifying, isolating
and using mTERT transcriptional and translational cis- and trans-acting
control elements. After the coding region of a mTERT gene has been
identified, the expression of natural, recombinant or synthetic
mTERT-encoding or other (i.e., antisense, ribozyme) mTERT nucleic acids
can be achieved by operably linking the coding region to a promoter
(that can be telomerase-specific or not, constitutive or inducible),
incorporating the construct into an expression vector, and introducing
the vector (or plasmid) into a suitable host cell. Synthetic procedures
may also be used. Typical vectors contain transcription and translation
terminators, transcription and translation initiation sequences, and
promoters useful for transcribing DNA into RNA.
[0133] The vectors optionally comprise generic expression cassettes
containing at least one independent terminator sequence, sequences
permitting replication of the cassette in eukaryotes, or prokaryotes,
or both (e.g., shuttle vectors), and selection markers for both
prokaryotic and eukaryotic systems. See, for example Roberts, Nature
(1987) 328:731; Berger (1987) supra; Schneider (1995) Protein Expr.
Purif. 6435:10; Sambrook and Ausubel. Product information from
manufacturers of biological reagents and experimental equipment also
provide information regarding known biological methods. Such
manufacturers include the SIGMA chemical company (Saint Louis, Mo.),
R&D systems (Minneapolis, Minn.), Pharmacia Biotech (Piscataway,
N.J.), Clontech Laboratories, Inc. (Palo Alto, Calif.), Aldrich
Chemical Company (Milwaukee, Wis.), GIBCO BRL Life Technologies, Inc.
(Gaithersburg, Md.), Fluka Chemica-Biochemika Analytika (Fluka Chemie
AG, Buchs, Switzerland), Applied Biosystems (Foster City, Calif.), as
well as many other commercial sources known to one of skill. Promoters
and vectors useful in regards in this invention can also be isolated
from natural sources, obtained from such sources as the ATCC or from
GenBank libraries, or prepared by synthetic methods, as described
herein.
[0134] Various embodiments of the invention include use of inducible
and constitutive promoters, depending on the expression system and
desired levels of control of expressed protein. For example, the
Tet-On/Tet-Off systems available from Clontech are useful in this
regard. Viral, prokaryotic or eukaryotic promoters can be incorporated
in expression vectors or expression cassettes. For example, highly
efficient viral promoters can be used in the expression vectors of the
invention, including cytomegalovirus (CMV) immediate early promoter,
Rous sarcoma virus (RSV), murine leukemia virus (SL3-3) and simian
virus 40 (SV40) early promoters. Other viral sequences, such as
adenovirus tripartite leader (TPL) sequences, can also increase
expression yields in eukaryotic expression systems (see, e.g., Lee
(1997) Mol. Cells 7:495-501).
[0135] The telomerase enzyme and mTERT of the invention can be
expressed in vectors which are transiently expressed in cells using,
e.g., episomal vectors such as those derived from vaccinia virus, see
Cooper (1997) Proc Natl Acad Sci USA 94:6450-6455; Muruve (1997)
Transplantation 64:542-546. Alternatively, mTERT coding sequences can
be inserted into the host cell genome becoming an integral part of the
host chromosomal DNA, using for example, retroviral vectors derived
from, e.g., SIV or HIV, see, e.g. Naldini (1996) Science 272:263-267;
Vanin (1997) J. Virol. 71:7820-7826; Zufferey (1997) Nat. Biotechnol.
15:871-875, describing attenuated lentiviral vector gene delivery in
vivo; Feng (1997) Nat Biotechnol 15:866-870, describing stable in vivo
gene transduction via adenoviral/retroviral chimeric vector.
[0136] Expression vectors can contain selection markers that confer a
selectable phenotype on transformed cells and sequences coding for
episomal maintenance and replication such that integration into the
host genome is not required. For example, the marker may encode
antibiotic resistance, particularly resistance to chloramphenicol,
kanamycin, G418, bleomycin and hygromycin, to permit selection of those
cells transformed with the desired DNA sequences, see, e.g.,
Blondelet-Rouault (1997) Gene 190:315-317; Aubrecht (1997) J.
Pharmacol. Exp. Ther. 281:992-997. Because selectable marker genes
conferring resistance to substrates like neomycin or hygromycin can in
certain cases only be utilized in tissue culture, chemoresistance genes
are also used as selectable markers in vitro and in vivo. Various
target cells are rendered resistant to anticancer drugs by transfer of
chemoresistance genes encoding P-glycoprotein, multidrug
resistance-associated protein-transporter, dihydrofolate reductase,
glutathione-S-transferase, O 6-alkylguanine DNA alkyltransferase, or
aldehyde reductase (Licht (1997) Stem Cells 15:104-111), and the like.
[0137] A DNA or RNA sequence coding for an mTERT protein, e.g., a cDNA
sequence encoding the full length mTERT, can be combined with
transcriptional (such as promoters and enhancers) and translational
regulatory sequences which will direct the transcription and
translation of the nucleic acid in a constitutive or a cell-specific or
tissue-specific manner. A wide variety of well known transcriptional
regulatory elements can be included in the vectors selected to express
an mTERT protein of the invention. mTERT promoter constructs which
direct the expression of mTERT in its native state are provided by the
invention. Additional mTERT promoters can be identified by analyzing
the 5' sequences of murine genomic clones. Sequences controlling
eukaryotic gene expression have been extensively studied, and promoters
have characteristic subsequences. For instance, promoter sequence
elements include the TATA box consensus sequence (TATAAT), which is
usually 20 to 30 base pairs upstream of the transcription start site.
In most instances, the TATA box is required for accurate transcription
initiation. In construction of recombinant expression cassettes of the
invention, a recombinant or isolated promoter fragment, either related
to the murine telomerase of this invention or heterologous thereto, may
be employed which will direct expression of the gene in all or only
some of the tissues of a transgenic organism, depending on the promoter
and conditions employed. Promoters that drive expression continuously
under physiological conditions, ie., "constitutive" promoters, are
active under most environmental conditions and states of development or
cell differentiation.
[0138] In some expression systems, to ensure optimal polypeptide
expression levels, a polyadenylation region at the 3'-end of the coding
region can be included. The polyadenylation region can be derived from
the natural gene or from any of a variety of other genes, e.g., see de
Moor (1997) Mol. Cell. Biol. 17:6419-6426.
[0139] ii. Transformation of Cells
with mTERT-vectors
[0140] There are several well-known methods of introducing nucleic
acids into bacterial and other cells, a process often called
"transforming," any of which may be used in the methods of the present
invention (see Sambrook). Techniques for transforming a wide variety of
animal and plant cells are well known and described in the technical
and scientific literature. See, e.g., Weising (1988) Ann. Rev. Genet.
22:421-477, for plant cells and Sambrook for animal and bacterial
cells. Specific examples of methods of expressing the novel murine
telomerase proteins of the invention are described below. For example,
these include fusion of the recipient cells with bacterial protoplasts
containing mTERT DNA, DEAE dextran transformation, infection with viral
vectors, and the like.
[0141] Methods for transforming bacterial cells are well known in the
art, and include, e.g., electroporation and heat shock of competent
cells (see, e.g., Sambrook). Bacterial strains which can be used to
express telomerase nucleic acid include, e.g., Escherichia coli,
Bacillus subtillus, Streptococcus cremoris, Streptococcus lactis,
Streptococcus thermophilus, Leuconostoc citrovorum, Leuconostoc
mesenteroides, Lactobacillus acidophilus, Lactobacillus lactis,
Bifidobacterium bifidum, Bifidobacteriu breve, and Bifidobacterium
longum. To simplify identification of colonies of bacteria transformed
with vectors containing the inserts, many cloning vectors have
restriction enzyme sites or other splicing sites located within a
coding sequence for an enzyme, such as, e.g., beta-galactosidase. If an
insert has successfully been inserted into the vector at the
restriction or splicing sites, the enzyme is either activated or
inactivated. After transformation of the bacteria with the vector,
colonies grown in the presence of isopropyl-D-thiogalactoside (IPTG)
(for beta-galactosidase) appear white, while the colonies derived from
a bacteria which did not incorporate the insert appear blue in the
presence of the substrate. Thus, even if the frequency of ligation of
the insert into the vector was low, one can pick the few colonies that
contain inserts over the many that do not.
[0142] In addition to bacterial expression systems, the TERT and
telomerase-associated proteins of this invention can be expressed in
other systems, such as yeast, insect (baculovirus), mammalian and plant
cells. The system used will depend on a variety of factors, including
activities and amounts desired.
[0143] Yeast expression systems, being eukaryotic, provide an
attractive alternative to bacterial systems for some applications; for
an overview of yeast expression systems, see Protein Engineering
Principles and Practice, eds. Cleland et al., Wiley-Liss, Inc. p 129
(1996). A variety of yeast vectors are publicly available. For example,
the expression vector pPICZ B (Invitrogen, San Diego, Calif.) has been
modified to create expression vectors of the invention to express the
mTERT of the invention in yeast, such as Pichia pastoris. Yeast
episomal plasmids comprising inducible promoters can be used for the
intracellular expression of protein. Vectors include the pYES2
expression vector (Invitrogen, San Diego, Calif.) and pBS24.1 (Boeke
(1984) Mol. Gen. Genet. 197:345); see also Jacobs (1988) Gene
67:259-269. Yeast promoters for yeast expression vectors suitable for
the expression of an mTERT include the inducible promoter from the
alcohol dehydrogenase gene, ADH2, also called the yeast alcohol
dehydrogenase II gene promoter (ADH2P) (La Grange (1997) Appl.
Microbiol. Biotechnol. 47:262-266). In another embodiment, the TERT to
be expressed can also be fused at the amino terminal end to the
secretion signal sequence of the yeast mating pheromone alpha-factor
(MF alpha 1S) and fused at the carboxy terminal end to the alcohol
dehydrogenase II gene terminator (ADH2T), see van Rensburg (1997) J.
Biotechnol. 55:43-53. The yeast alpha mating pheromone signal sequence
allows for secretion of the expressed telomerase. Direct intracellular
expression of mTERT is useful for a variety of cell-based screens or
mTERT protein production or telomerase enzyme reconstitution.
[0144] Yeast strains which can be used to express exogenous nucleic
acids include Pichia pastoris, Hansenula polymorpha, Torulopsis holmil,
Saccharomyces fragilis, Saccharomyces cerevisiae, Saccharomyces lactis,
and Candida pseudotropicalis. A large number of vectors are available
for S. cerevisiae. Kluyveromyces lactis and the methylotrophs Hansenula
polymorphas and Pichia pastoris can offer certain advantages over
baker's yeast S. cerevisiae for the production of certain proteins, see
Gellissen (1997) Gene 190:87-97; Wegner (1990) FEMS Microbiol. Rev.
87:279.
[0145] The present invention also provides insect expression systems to
express large amounts of recombinant mTERT and telomerase enzyme of the
invention. A commonly used insect system utilizes Spodoptera frugiperda
infected with a baculovirus, such as Autographa californica nuclear
polyhedrosis virus. This virus can be used to infect Sf21 (Deutschmann
(1994) Enzyme Microb Technol 16:506-512) or Sf9 cells (MaxBac 2.0,
Invitrogen, San Diego, Calif.) (Zhu (1996) J. Virol. Methods 62:71-79)
derived from Spodoptera frugiperda, High Five cells derived from
Trichoplusia ni insect cells (Parrington (1997) Virus Genes 14:63-72),
and Lymantria dispar (Vaughn (1997) In Vitro Cell Dev Biol Anim
33:479-482); see also Grabherr (1997) Biotechniques 22:730-735).
Baculovirus transfer vectors can be used to replace the wild-type
AcMNPV polyhedron gene with a heterologous gene of interest. Sequences
that flank the polyhedrin gene in the wild-type genome are positioned
5' and 3' of the expression cassette on the transfer vectors. Following
cotransfection with AcMNPV DNA, a homologous recombination event occurs
between these sequences resulting in a recombinant virus carrying the
gene of interest and the polyhedrin or p10 promoter. Baculovirus
expression vectors are publicly available, such as pAC360 (Invitrogen,
San Diego, Calif.). In addition to manufacturers' instructions
accompanying the commercially available baculovirus systems, see, e.g.,
"Current Protocols in Molecular Biology," Ausubel, Chapter 16.
[0146] The present invention also provides methods and reagents for
recombinant mTERT and telomerase enzyme expression in plant cell
systems. Constitutive promoters of plants include the cauliflower
mosaic virus (CaMV) 35S transcription initiation region, the 1'- or
2'-promoter derived from T-DNA of Agrobacterium tumafaciens, the
promoter of the tobacco mosaic virus and transcription initiation
regions from various plant genes known to those of skill in the art.
The promoter may direct expression in only a specific tissue
(tissue-specific promoters) or may be under environmental control
(inducible promoters). Examples of tissue-specific plant promoters
under developmental control include promoters that initiate
transcription only in certain tissues, such as fruit, seeds, or
flowers. The tissue specific E8 promoter from tomato is particularly
useful for directing gene expression so that a desired gene product is
located in fruits. Other suitable promoters include those from genes
encoding embryonic storage proteins. Examples of environmental
conditions that may affect transcription by inducible promoters include
anaerobic conditions, elevated temperature, or the presence of light.
[0147] Plants can be transformed using viral vectors, such as, for
example, tobacco mosaic virus derived vectors, to express recombinant
telomerase enzyme or mTERT of the invention. Selection and construction
of vectors and techniques for transforming a wide variety of plant
cells are well known, e.g., see Hamamoto, U.S. Pat. No. 5,618,699. For
example, mTERT constructs can be combined with suitable T-DNA flanking
regions and introduced into a conventional Agrobacterium tumefaciens
host vector. The virulence functions of the Agrobacterium tumefaciens
host will direct the insertion of the construct and adjacent marker
into the plant cell DNA when the cell is infected by the bacteria.
Agrobacterium tumefaciens-mediated transformation techniques, including
disarming and use of binary vectors, are well described in the
scientific literature. See, e.g., Horsch, Science (1984) 233:496, and
Fraley (1983) Proc. Natl Acad. Sci USA 80:4803; see also Chong (1997)
Transgenic Res. 6:289-296, describing Agrobacterium
tumefaciens-mediated leaf disc transformation methods. Plant
regeneration from cultured protoplasts is described in Evans,
PROTOPLASTS ISOLATION AND CULTURE, HANDBOOK OF PLANT CELL CULTURE, pp.
124-176, Macmillian Publishing Company, New York, 1983; and Binding,
REGENERATION OF PLANTS, PLANT PROTOPLASTS, pp. 21-73, CRC Press, Boca
Raton, 1985. Regeneration can also be obtained from plant callus,
explants, organs, or parts thereof. Such regeneration techniques are
described generally in Klee (1987) Ann. Rev. of Plant Phys. 38:467;
Jafari (1995) Acta Biol. Hung. 46:51-59.
[0148] The invention provides methods and reagents for expression of
mTERT and telomerase enzyme in mortal, transformed, or transformed
immortal indefinitely proliferating mammalian cells using a wide
variety of combinations of transcriptional control elements (e.g.,
promoters and enhancers), translational control elements, vectors
(plasmid, viral, episomal, integrating), selectable marker genes, and
related agents and cells. In some embodiments, endogenous mTERT, or
mTERT and mTERC, activity can be debilitated, modified or fully
deleted, ie., "knocked out," before insertion of vectors encoding
modified endogenous or exogenous TERT (e.g., hTERT), TERC (e.g., hTERC)
or other telomerase enzyme-associated compositions of the invention.
The endogenous mTERT can be debilitated or deleted in either one or
both alleles. The endogenous mTERC can also be debilitated or deleted
in either one or both alleles. In an alternative embodiment, the mTERT
of the invention or a variant, such as a deletion variant, is
introduced into the cell to produce such a "knock-out" cell or animal.
[0149] Promoters can be constitutive or inducible, as described above.
Vectors and promoters can be "transcriptionally targeted" to restrict
the expression of the TERT sequence to appropriate cells. If the
expression is to be used in a therapeutic method, such as gene therapy,
there may be a therapeutic window for certain proteins such that levels
of expression below and above certain thresholds may be ineffective or
toxic, requiring vectors that allow exogenous control of expression, so
that levels of the therapeutic protein can be raised or lowered
according to therapeutic need. See e.g., Miller (1997) Hum. Gene Ther.
8:803-815; Walther (1996) J. Mol. Med. 74:379-392; Walther (1997) Gene
Ther. 4:544-552.
[0150] In one embodiment of the invention, recombinant mTERT is
expressed in normal, diploid mortal cells to create an indefinitely
proliferating cell or to immortalize them. Illustrative vectors
incorporating mTERT genes and coding sequences for the production of
indefinitely proliferating and immortal B lymphocytes to obtain cells
for monoclonal antibody production include, e.g., adenovirus-based
vectors (Cantwell (1996) Blood 88:4676-4683; Ohashi (1997) Proc Natl
Acad Sci USA 94:1287-1292), Epstein-Barr virus-based vectors (Mazda
(1997) J Immunol Methods 204:143-151), adenovirus-associated virus
vectors, Sindbis virus vectors (Strong (1997) Gene Ther 4: 624-627),
Herpes simplex virus vectors (Kennedy (1997) Brain 120:1245-1259) and
retroviral vectors (Schubert (1997) Curr Eye Res 16:656-662). The
present invention provides a variety of vectors for introducing mTERT
and telomerase enzyme into cells to produce an indefinitely
proliferating or immortal normal cell that in turn produces a
commercially desirable protein, such as pituitary cells that make
hormones, like growth hormone, and is karyotypically normal.
Epstein-Barr virus episomal vectors (Horlick (1997) Protein Expr.
Purif. 9:301-308), and plasmid DNA (Lowrie (1997) Vaccine 15: 834-838)
can also be used to express the mTERT and/or the telomerase enzyme of
the invention in vivo or ex vivo. The use of mammalian tissue cell
culture to express polypeptides is discussed generally in Winnacker,
From Genes to Clones, VCH Publishers, NY, N.Y., 1987)
[0151] vii. Optimizing Expression of
mTERT and Telomerase Enzyme
[0152] In bacterial and other expression systems, codon usage is known
to present a potential impediment to high-level gene expression. "Rare"
codons, depending on their frequency and context in an mRNA, can have
an adverse effect on levels of protein translated therefrom. The
problem, if encountered, can be alleviated by modification of the
relevant codons or by coexpression of the cognate tRNA genes or by
other means (see Kane (1995) Curr. Opin. Biotechnol. 6:494-500). Use of
protease-deficient host strains can also increase yields from bacterial
expression systems, see Makrides (1996) Microbiol Rev 60:512-538.
[0153] One can also optimize levels of expression of mTERT by vector
design modifications, such as using exogenous transcriptional
regulatory elements. For example, as discussed below, the
myeloproliferative sarcoma virus (MPSV) LTR promoter consistently
drives higher expression levels in some mammalian cell lines (see Dirks
(1994) Gene 149:389-390).
[0154] Generally, those of skill in the art recognize that nucleic
acids having certain specific sequences can be poorly expressed in one
cell and expressed well in other cells. Thus, alternative embodiments
of the invention include expression systems that do not incorporate
extraneous sequences, i.e., non-coding sequences such as 3'
untranslated sequences from a cDNA, with the desired coding sequence.
Thus, one optimization method involves removing all extraneous
sequences from the coding sequence insert. This method can in some
circumstances increase protein expression 5 to 10 fold in bacteria,
insect, yeast, mammalian and other cells expression systems.
[0155] Gene amplification, whether by higher vector copy number or by
replication of a gene in a chromosome, can increase yields of
recombinant proteins in mammalian and other cells. One amplification
method for heterologous gene expression in mammalian cells is based on
the stable transfection of cells with long, linear DNA molecules having
several copies of complete expression units coding for the gene of
interest linked to one terminal unit coding for a selectable marker.
Gene amplification of the gene of interest can be achieved by linking
it to a dihydrofolate reductase (Dhfr) gene and administering
methotrexate to the transfected cells; this method can increase
recombinant protein production many fold (see Monaco (1996) Gene
180:145-150).
[0156] vii Use of Cells, Animals and
Plants Expressing Recombinant mTERT
[0157] The invention provides in vivo assays using transformed cells
and transgenic animals expressing recombinant mTERT. These living assay
systems can be used to screen for modulators of mTERT; the endogenous
TERT, or TERT and TERC, in the non-human cells or animal can be first
modified, debilitated, or "knocked out" before reconstituting
telomerase activity with mTERT, or, mTERT and mTERC. The reconstitution
can be with or without the co-introduction of mTERC or hTERC and/or
other telomerase enzyme-associated components. In one embodiment, the
invention provides screening assays to identify modulators of mTERT and
telomerase enzyme activity in vitro and in vivo, such as in animal and
plant cells and whole organisms. The screening assays can utilize mTERT
or telomerase enzyme derived by a full or partial reconstitution of
telomerase activity, or by an augmentation of existing activity. The
assay or screens provided by the invention can be used to test for the
ability of telomerase to synthesize telomere DNA or to test for any one
or all or of the "partial activities" of mTERT. The assay can
incorporate ex vivo modification of cells which have been manipulated
to express mTERT with or without an RNA moiety (such as mTERC or hTERC)
or associated proteins, and these can be reimplanted into an animal,
and so used for in vivo testing.
[0158] The invention also provides transformed cells, transgenic
animals and methods for expressing mTERT in such animals, as well as
otherwise normal cells that can be used to express compositions of
interest and can be used in related methods. Such transformed cells and
transgenic animals can express the exogenous mTERT either alone or
co-expressed with an RNA moiety (i.e., mTERC or hTERC) or other
telomerase-associated proteins. The invention provides transgenic
animals and recombinant cells to be used, e.g., as bioreactors (Khillan
(1997) Methods Mol. Biol. 63:327-342) to produce large amounts of mTERT
or telomerase enzyme.
[0159] The mTERT-expressing nucleic acid of the invention may be
introduced into the genome of an animal or plant host organism by a
variety of conventional techniques (Jacenko (1997) Methods Mol. Biol.
62:399-424). For example, recent advances in transgenic and
gene-targeting approaches allow a sophisticated manipulation of the
mouse genome by gene addition, gene deletion, or gene modifications,
making this animal convenient for the methods of the invention (Franz
(1997) J. Mol. Med. 75:115-129; Peterson (1997) Genet. Eng. (N.Y.)
19:235-255). Many cloning vectors for transgene construction are known
in the art, e.g., Yang (1997) Biotechniques 22:1032-1034. There are two
well-established procedures for simple introduction of DNA into animal
genomes, pronuclear DNA injection and transduction using a retrovirus
(Wei (1997) Annu. Rev. Pharmacol. Toxicol. 37:119-141). Microinjection
techniques for use in introducing DNA into animals and plants are known
in the art and described in the scientific and patent literature (e.g.,
Bartoli (1997) Mol. Cell. Biochem. 172:103-109). The introduction of
DNA constructs into cells using polyethylene glycol precipitation is
described, e.g., in Paszkowski (1984) EMBO J. 3:2717. Electroporation
techniques are described, e.g., in Fromm (1985) Proc. Natl. Acad. Sci.
USA 82:5824. Ballistic transformation techniques are described, e.g.,
in Klein (1987) Nature 327:70; Zelenin (1997) FEBS Lett 414:319-322.
[0160] The invention also provides transgenic plants and methods for
expressing the TERT and telomerase enzyme compositions of the invention
and screening assays to identify modulators of telomerase activity in
such plants. In plants, the DNA construct may be introduced directly
into the genomic DNA of the plant cell using techniques such as
electroporation and microinjection of plant cell protoplasts
(Schnorf(1991) Transgenic Res. 1:23-30), or the DNA constructs can be
introduced directly to plant tissue using ballistic methods, such as
DNA particle bombardment (Baum (1997) Plant J. 12:463-469). As
discussed above, plant virus vectors such as tobacco mosaic virus
containing the telomerase sequences of the invention can be used to
inoculate a plant (Rouwendal (1997) Plant Mol Biol 33:989-999).
[0161] e. mTERT-deficient "Knockout"
Mouse Cells and Animals
[0162] In one embodiment, the mTERT nucleic acids and reagents of the
invention are used to create mouse cells and animals in which the
endogenous mTERT is deleted, modified, supplemented or inhibited. One
or several units of the endogenous telomerase enzyme complex, in
addition to mTERT, such as mTERC, can also be deleted, modified,
supplemented or inhibited. For example, mTERT and mTERC can be deleted,
modified or inhibited on either one or both alleles. The cells or
animals can be reconstituted with a wild-type or modified mTERT or an
exogenous TERT, including for example, a TERT from a non-mouse species,
such as hTERT. In TERC knockout cells, a TERC from a non-mouse species,
such as hTERC, can be introduced. Other telomerase enzyme complex
associated molecules can also be introduced into the knockout cell or
animal. Alternative methodologies for constructing knockout cells or
animals and methods of screening and selection, are all well known in
the art; an illustrative example is set forth below.
[0163] Construction of a "knockout" cell and animal is based on the
premise that the level of expression of a particular gene in a
mammalian cell can be decreased or completely abrogated by introducing
into the genome a new DNA sequence (e.g., an mTERT or other nucleic
acid construct of the invention) that serves to interrupt some portion
of the DNA sequence of the gene to be suppressed. To prevent expression
of functional enzyme, simple mutations that either alter the reading
frame or disrupt the promoter can be suitable. To upregulate
expression, a native promoter can be substituted with a heterologous
promoter that induces higher levels of transcription. Also, "gene trap
insertion" can be used to disrupt a host gene, and mouse embryonic stem
(ES) cells can be used to produce knockout transgenic animals, as
described herein and, e.g., in Holzschu (1997) Transgenic Res 6: 97-106.
[0164] The insertion of the exogenous sequence is typically by
homologous recombination between complementary nucleic acid sequences.
Thus, the exogenous sequence, which is typically an mTERT nucleic acid
in this invention, is some portion of the target (mTERT) gene to be
modified, such as exonic, intronic or transcriptional regulatory
sequences, or any genomic sequence which is able to affect the level of
the target gene's expression; or a combination thereof. The construct
can also be introduced into other (i.e., non-mTERT gene) locations in
the genome. Gene targeting via homologous recombination in
pluripotential embryonic stem cells allows one to modify precisely the
gene of interest.
[0165] The exogenous sequence is typically inserted in a construct,
usually also with a marker gene to aid in the detection of the knockout
construct and/or a selection gene. The construct can be any of a
variety of expression vectors, plasmids, and the like, as described
above. The knockout construct is inserted in a cell, typically an
embryonic stem (ES) cell, using a variety of techniques, as described
above. The insertion of the exogenous DNA usually occurs by homologous
recombination. The resultant transformed cell can be a single gene
knockout (i.e., only one of the two copies of the endogenous mTERT has
been modified) or a double gene knockout. The knockout construct can be
integrated into one or several locations in the cell's genome due to
the random nature of homologous recombination events; however, the
recombination does occur between regions of sequence complementarity.
Typically, less than one to five percent of the ES cells that take up
the knockout construct will actually integrate exogenous DNA in these
regions of complementarity; thus, identification and selection of cells
with the desired phenotype is usually necessary and a selection or
marker sequence is usually incorporated into the construct for this
purpose. Cells which have incorporated the construct are selected for
prior to inserting the genetically manipulated cell into a developing
embryo; for example, the cells are subjected to positive selection
(using G418, for example, to select for neomycin-resistance) and
negative selection (using, for example, FIAU to exclude cells lacking
thymidine kinase). A variety of selection and marker techniques are
well known in the art, e.g., antibiotic resistance selection or
beta-galactosidase marker expression can be used and are further
described herein. Alternatively, insertion of the exogenous sequence
and levels of expression of the endogenous mTERT or marker/selection
genes can be detected by hybridization or amplification techniques or
by antibody-based assays, as described herein.
[0166] After selection of manipulated cells with the desired phenotype,
i.e., complete or partial inability to express mTERT, the cells are
inserted into a mouse embryo. Insertion can be accomplished by a
variety of techniques, such as microinjection, in which about 10 to 30
cells are collected into a micropipet and injected into embryos that
are at the proper stage of development to integrate the ES cell into
the developing embryonic blastocyst, at about the eight cell stage,
which for mice is about 3.5 days after fertilization. The embryos are
obtained by perfusing the uterus of pregnant females. After the ES cell
has been introduced into the embryo, it is implanted into the uterus of
a pseudopregnant foster mother, which is typically prepared by mating
with vascectomized males of the same species. In mice, the optimal time
to implant is about two to three days pseudopregnant. Offspring are
screened for integration of the mTERT nucleic acid sequences and the
modified telomerase activity phenotype. Offspring that have the desired
phenotype are crossed to each other to generate a homozygous knockout.
If it is unclear whether germline cells of the offspring have modified
mTERT, they can be crossed with a parental or other strain and the
offspring screened for heterozygosity of the desired trait. The
heterozygotes can be crossed with each other to produce mice homozygous
for modified mTERT genomic sequence. While the above described
methodology describes a typical protocol, any technique can be used to
create, screen for, propagate, mTERT knockout mice, e.g., see Bijvoet
(1998) Hum. Mol. Genet. 7:53-62; Moreadith (1997) J. Mol. Med.
75:208-216; Tojo (1995) Cytotechnology 19:161-165; Mudgett (1995)
Methods Mol. Biol. 48:167-184; Longo (1997) Transgenic Res. 6:321-328;
U.S. Pat. Nos. 5,616,491 (Mak, et al.); 5,464,764; 5,631,153;
5,487,992; 5,627,059; 5,272,071; and, WO 91/09955, WO 93/09222, WO
96/29411, WO 95/31560, and WO 91/12650. Thus, the invention provides
for the use of the mTERT reagents of the invention to produce
"knockout" mouse cells and animals, and their progeny, in which one or
several units of the endogenous telomerase enzyme complex have been
deleted, modified or inhibited. These cells and animals can be further
reconstituted with wild type or modified endogenous mTERT or exogenous
TERT, such as hTERT, or other telomerase enzyme associated components,
as described herein.
[0167] f. Site-specific Mutations
[0168] The invention also provides for an mTERT and telomerase enzyme
that have been modified in a site-specific manner to modify or delete
any or all functions of the telomerase enzyme or the mTERT protein.
Such a modified telomerase provides for means to alter, especially
inhibit, telomerase activity in cells and animals and so to control the
unlimited proliferative capacity of cells, such as cancer cells. Such
telomerases and mTERT proteins can also be employed in the screens of
the invention to discover therapeutic agents. For example, the mTERT
can be engineered to lose its ability to bind substrate DNA, to bind an
RNA moiety (as mTERC or hTERC), to catalyze the addition of telomeric
DNA, to bind deoxynucleotide substrate, to have nucleolytic activity,
to bind telomere-associated proteins or chromosomal structures, and the
like. The resulting "mutant proteins" or "muteins" can be used to
identify compounds that specifically modulate one, several, or all
functions or activities of the mTERT protein or telomerase enzyme.
Site-specific mutations can be introduced into mTERT-encoding nucleic
acid by a variety of conventional techniques, well described in the
scientific and patent literature. For example, one rapid method to
perform site-directed mutagenesis efficiently is the overlap extension
polymerase chain reaction (OE-PCR) (Urban (1997) Nucleic Acids Res.
25:2227-2228). Other illustrative examples include: Ke (1997) Nucleic
Acids Res 25:3371-3372, and Chattopadhyay (1997) Biotechniques
22:1054-1056, describing PCR-based site-directed mutagenesis
"megaprimer" method; Bohnsack (1997) Mol. Biotechnol. 7:181-188;
Ailenberg (1997) Biotechniques 22:624-626, describing site-directed
mutagenesis using a PCR-based staggered re-annealing method without
restriction enzymes; Nicolas (1997) Biotechniques 22:430-434,
site-directed mutagenesis using long primer-unique site elimination and
exonuclease III.
[0169] In another system, a correctly folded, complete protein and its
mutagenized encoding mRNA both remain attached to a ribosome and can be
assessed for alterations in ligand-binding properties of the native
protein. Libraries of native folded proteins with engineered
site-specific mutations can now be screened while "evolving" in a
cell-free system without the transformation or other constraints
imposed when using a host cell (Hanes (1997) Proc. Natl. Acad. Sci. USA
94:4937-4942). Modified mTERT proteins of the invention can be produced
by site-directed mutagenesis and/or chemical modification methods to
introduce unnatural amino acid side chains (see Paetzel (1997) J. Biol.
Chem. 272:9994-10003 for general methodology).
[0170] For example, the invention provides for an mTERT protein that is
modified in a site-specific manner and optionally modified to
facilitate cloning into bacterial, mammalian, yeast and/or insect
expression vectors without any 5' and/or 3' untranslated mTERT
sequence, or optionally with altered codon usage produced
synthetically. In some circumstances, minimizing the amount of
non-protein encoding sequence allows for improved protein production
(yield) and/or increase mRNA stability.
[0171] As an illustrative example, one can place an additional
restriction endonuclease site just upstream (5') to the start (ATG)
codon of mTERT cDNA in accordance with the teaching herein. The
creation of a restriction site just 5' to the coding region for the
protein allows for ready construction of a wide variety of vectors for
the production of fusion proteins, including fusion labels and peptides
capable of being bound by predefined antibodies (TAGs), i.e., for
immuno- or other detection and purification schemes. This modified
mTERT provided by the invention can be conveniently used for the
construction of expression plasmids of the invention.
2. Detection and Purification of mTERT
[0172] a. Detection of mTERT and
Telomerase Enzyme
[0173] The invention also provides methods and reagents for detecting
or quantitating telomerase enzyme and/or mTERT by a variety of methods.
For example, mTERT can be detected and quantified by incorporating
functional activity assays of the invention, by immunological assays
utilizing a variety of anti-mTERT antibodies provided by the invention,
and by nucleic acid-based methodologies, examples of which are also
described in detail below.
[0174] i. Antibody Production
[0175] In one embodiment, the invention provides antibodies that bind
one mTERT specie specifically or mTERTs generally, and so can be used
to identify and isolate any mTERT species provided for in the invention
or to identify a single allele, homologue or isoform of mTERT.
Antibodies which can identify any mTERT specie can be generated by
using as antigens peptides containing structural features, i.e.,
motifs, common to all mTERT species, as described herein. In general,
the antibodies of the invention can be used to identify, purify, or
inhibit any or all activity of murine telomerase enzyme complex and
mTERT protein.
[0176] Antibodies can act as antagonists of telomerase enzyme activity
in a variety of ways, for example, by preventing the telomerase complex
or nucleotide from binding to its DNA substrates, by preventing the
components of telomerase enzyme from forming an active complex, by
maintaining a functional (telomerase enzyme complex) quaternary
structure or by binding to one of the enzyme's active sites or other
sites that have allosteric effects on activity (the different partial
activities of telomerase are described in detail elsewhere in this
specification). General methods for producing the antibodies of the
invention are described below.
[0177] Methods of producing polyclonal and monoclonal antibodies are
known to those of skill in the art and described in the scientific and
patent literature, see, e.g., Coligan, CURRENT PROTOCOLS IN IMMUNOLOGY,
Wiley/Greene, N.Y. (1991); Stites (eds.) BASIC AND CLINICAL IMMUNOLOGY
(7th ed.) Lange Medical Publications, Los Altos, Calif., and references
cited therein ("Stites"); Goding, MONOCLONAL ANTIBODIES: PRINCIPLES AND
PRACTICE (2d ed.) Academic Press, New York, N.Y. (1986); Kohler (1975)
Nature 256:495; Harlow and Lane (1988) ANTIBODIES, A LABORATORY MANUAL,
Cold Spring Harbor Publications, New York. Such techniques include
selection of antibodies from libraries of recombinant antibodies
displayed in phage ("phage display libraries") or similar on cells.
See, Huse (1989) Science 246:1275; Ward (1989) Nature 341:544;
Hoogenboom (1997) Trends Biotechnol. 15:62-70; Katz (1997) Annu. Rev.
Biophys. Biomol. Struct. 26:27-45. Recombinant antibodies can be
expressed by transient or stable expression vectors in mammalian cells,
as in Norderhaug (1997) J. Immunol Methods 204:77-87; or in yeast,
Boder (1997) Nat. Biotechnol. 15:553-557.
[0178] To produce large amounts of antibodies for use in, for example,
immunoaffinity purification or diagnostics, a number of immunogens
provided by the invention may be used. Telomerase enzyme or mTERT
isolated or purified from a natural source (see co-pending U.S. Ser.
No. 08/833,377, filed Apr. 4, 1997), from a recombinant protein
isolated from transformed cells provided by the present invention, or
isolated as a synthetically produced composition, can be used as
immunogens for the production of monoclonal or polyclonal antibodies.
Naturally occurring murine telomerase enzyme or mTERT proteins or
recombinant mTERT and/or telomerase enzyme can be used either in pure
or impure form. Synthetic peptides are made using any portion of the
mTERT amino acid sequence for use as immunogens, particularly peptides
comprising the motif structures described herein. The peptides can be
used alone or conjugated to another composition as immunogens.
[0179] Methods for the production of polyclonal and monoclonal
antibodies are known to those of skill in the art. In brief, an
immunogen is mixed with an adjuvant, as described above, and animals
are immunized. The animal's immune response to the immunogen
preparation is monitored by taking test bleeds and determining the
titer of reactivity to the immunogen. When appropriately high titers of
antibody to the inununogen are obtained, blood is collected from the
animal and antisera prepared. Further fractionation of the antisera to
enrich for antibodies reactive to the protein can be done (Harlow and
Lane, supra). Various illustrative peptides, proteins and fusion
proteins of the invention can be used to generate such polyclonal
antibodies.
[0180] Large amounts of monoclonal antibodies for use in immunoaffinity
purification or immunoassays may be obtained by various techniques
familiar to those skilled in the art. Briefly, spleen cells from an
immunized animal are immortalized, commonly by fusion with a myeloma
cell. Alternative methods of immortalization include transformation
with Epstein Barr Virus, oncogenes, or retroviruses, or other methods
well known in the art. In the antibody-generating methods of the
instant invention, colonies arising from single immortalized cells are
screened for production of antibodies of the desired specificity and
affinity for murine telomerase enzyme and/or mTERT protein. The yield
of the monoclonal antibodies produced by such cells may be enhanced by
various techniques, including injection into the peritoneal cavity of a
vertebrate host. Alternatively, one may isolate DNA sequences which
encode a monoclonal antibody or a binding fragment thereof by screening
a DNA library from appropriate human B cells, ie., immunized according
to the general protocol outlined in Huse (1989) Science, supra.
[0181] The concentration of telomerase enzyme or mTERT protein can be
measured by a variety of immunoassay methods of the invention.
Generally, immunoassays are described in Stites, supra. The
immunoassays of the present invention can be performed in any of
several configurations; for background information see ENZYME
IMMUNOASSAY, Maggio, ed., CRC Press, Boca Raton, Fla. (1980); Tijssen,
Harlow and Lane, supra.
[0182] To make the anti-mTERT sera of the invention (e.g., for use in
an immunoassay for telomerase) natural, recombinant or synthetic mTERT
or telomerase protein preparations, or immunogenic fragments thereof,
are produced as described herein. Animals, e.g., inbred strains of mice
or rabbits, can be immunized with an mTERT, such as the polypeptide of
SEQ ID NO:2, or with isoforms, homologues or immunogenic fragments
thereof, alone or using a standard adjuvant, such as Freund's adjuvant,
and a standard immunization protocol. Alternatively, a synthetic
peptide derived from the sequences disclosed herein and conjugated to a
carrier protein can be used an immunogen. Polyclonal sera are collected
and titered against the telomerase in an immunoassay, for example, a
solid phase immunoassay with the telomerase immobilized on a solid
support. Polyclonal antisera with a titer of, e.g., 10<4 > or
greater are selected and tested for their cross reactivity against
homologous proteins from other organisms and/or non-telomerase protein,
using, e.g., a competitive binding immunoassay. Specific monoclonal and
polyclonal antibodies and antisera will usually bind with a KD of at
least about 1 [mu]M, preferably at least about 0.1 [mu]M or better, and
most preferably, 0.01 [mu]M or less. However, the antisera and
monoclonal antibodies of the invention are not limited to these binding
affinities.
[0183] ii. Immunological Binding Assays
[0184] Immunological binding assays (e.g. U.S. Pat. Nos. 4,366,241;
4,376,110; 4,517,288; and 4,837,168) are known in the art. For a
review, see also METHODS IN CELL BIOLOGY Vol. 37: Antibodies in Cell
Biology, Asai, ed. Academic Press, Inc. New York (1993); and Stites,
supra. Immunological binding assays (or immunoassays) typically utilize
a capture agent to bind specifically to and often immobilize the
analyte. The capture agent is a moiety that specifically binds to the
analyte. In one embodiment of the present invention, the capture agent
is an antibody that specifically binds to telomerase enzyme or mTERT.
[0185] Immunoassays also often utilize a labeling agent to specifically
bind to and label the binding complex formed by the capture agent and
the analyte, as described above. The labeling agent may itself be, for
example, one of the moieties comprising the antibody/analyte complex:
the labeling agent can be a labeled mTERT or a labeled anti-mTERT
antibody. Alternatively, the labeling agent may be a third moiety, such
as another antibody, that specifically binds to the antibody-mTERT
complex. The labeling agent can be, for example, a second anti-mTERT
antibody bearing a label. The second antibody may lack a label, but it
may, in turn, be bound by a labeled third antibody specific to
antibodies of the species from which the second antibody is derived.
The second can be modified with a detectable moiety, such as biotin, to
which a third labeled molecule can specifically bind, such as
enzyme-labeled streptavidin. Other proteins capable of specifically
binding immunoglobulin constant regions, such as protein a or protein G
may also be used as the label agent. These proteins are normal
constituents of the cell walls of streptococcal bacteria and exhibit a
strong non-immunogenic reactivity with immunoglobulin constant regions
from a variety of species (see, generally Akerstrom (1985) J. Immunol.
135:2589-2542; Chaubert (1997) Mod. Pathol. 10:585-591).
[0186] Throughout the assays, incubation and/or washing steps may be
required after each combination of reagents. Incubation steps can vary
from about 5 seconds to several hours, preferably from about 5 minutes
to about 24 hours. However, the incubation time will depend upon the
assay format, analyte, volume of solution, concentrations, and the
like. Usually, the assays will be carried out at ambient temperature,
although they can be conducted over a range of temperatures, such as
10[deg.] C. to 40[deg.] C.
[0187] (1) Non-competitive Assay
Formats
[0188] Immunoassays for detecting murine telomerase enzyme and mTERT
protein may be, for example, either competitive or noncompetitive.
Noncompetitive immunoassays are assays in which the amount of captured
analyte (as mTERT) is directly measured. In one preferred "sandwich"
assay, for example, the capture agent (anti-mTERT antibodies) can be
bound directly to a solid substrate where they are immobilized. These
immobilized antibodies then capture protein present in the test sample.
The mTERT protein thus immobilized is then bound by a labeling agent,
such as a second anti-mTERT antibody bearing a label. Alternatively,
the second anti-mTERT antibody may lack a label, but it may, in turn,
be bound by a labeled third antibody specific to antibodies of the
species from which the second antibody is derived. The second can be
modified with a detectable moiety, such as biotin, to which a third
labeled molecule can specifically bind, such as enzyme-labeled
streptavidin.
[0189] (2) Competitive Assay Formats
[0190] In competitive assays, the amount of analyte (telomerase)
present in the sample is measured indirectly by measuring the amount of
an added (exogenous) analyte (mTERT) displaced (or competed away) from
a capture agent (anti-TERT antibody) by the analyte present in the
sample. In one competitive assay, a known amount of, in this case
mTERT, usually labeled, is added to the sample, and the sample is then
contacted with a capture agent, in this case an antibody that
specifically binds mTERT. The amount of labeled mTERT bound to the
antibody is inversely proportional to the concentration of mTERT
present in the sample. In another embodiment, the antibody is
immobilized on a solid substrate. The amount of mTERT bound to the
antibody may be determined either by measuring the amount of mTERT
present in an mTERT/antibody complex, or alternatively by measuring the
amount of remaining uncomplexed mTERT. The amount of mTERT may be
detected by providing a labeled mTERT molecule.
[0191] A hapten inhibition assay is another competitive assay. In this
assay a known analyte, in this case mTERT, is immobilized on a solid
substrate, a known amount of anti-mTERT antibody is added to the
sample, and the sample is then contacted with the immobilized mTERT. In
this case, the amount of anti-mTERT antibody bound to the immobilized
mTERT is inversely proportional to the amount of telomerase or mTERT
present in the sample. The amount of immobilized antibody is determined
by detecting either the immobilized fraction of antibody or the
fraction of the antibody that remains in solution. Detection may be
direct where the antibody is labeled or indirect by the subsequent
addition of a labeled moiety that specifically binds to the antibody,
as described above.
[0192] Immunoassays in the competitive binding format can be used for
crossreactivity determinations to permit one of skill to determine if a
protein or enzyme complex is an mTERT or murine telomerase enzyme. For
example, an mTERT of SEQ ID NO:2 can be immobilized to a solid support,
a putative mTERT protein is added to the assay to compete with the
binding of the anti-mTERT sera to an immobilized mTERT. The ability of
the protein to compete with the binding of the antisera to the
immobilized mTERT is compared to the ability of soluble mTERT (same as
on the solid support) to compete with the binding of the antisera to
the immobilized mTERT.
[0193] (3) Other Assay Formats
[0194] The present invention also provides methods for Western blot
(inmmunoblot) analysis to detect and/or quantify the presence of mTERT
or telomerase enzyme protein in a sample. The technique generally
comprises separating sample proteins by gel electrophoresis on the
basis of molecular weight, transferring the separated proteins to a
suitable solid support (such as a nitrocellulose filter, a nylon
filter, or derivatized nylon filter) and incubating the sample with
antibodies that specifically bind mTERT. The anti-mTERT antibodies
specifically bind to mTERT on the solid support. These antibodies may
be directly labeled or alternatively may be subsequently detected using
a second labeled antibody that specifically binds to the anti-mTERT
antibody.
[0195] Antibodies can also be used to probe expression libraries, see
Young (1982) Proc. Natl. Acad Sci. USA 80:1194. In general, a cDNA
expression library may be prepared from commercially available kits or
using readily available components. Phage (Hurst (1997) Methods Mol
Biol 69:155-159), bacteria (Davis (1997) Proc. Natl. Acad. Sci. USA
94:2128-2132), insect cells (Granziero (1997) J. Immunol. Methods
203:131-139), yeast, and animal cells (Xenopus oocytes) can be used.
One selects mRNA from a source that is optionally enriched with the
target mRNA or in which the protein is abundant and creates cDNA which
is then ligated into a vector, and the vector is transformed into the
library host cells for immunoscreening. Screening involves binding and
identification of antibodies bound to specific proteins on cells or
immobilized on a solid support such as nitrocellulose or nylon
membranes. Positive clones are selected for purification to homogeneity
and the isolated cDNA then prepared for expression in the desired host
cells. See also METHODS OF CELL BIOLOGY, VOL. 37, Antibodies in Cell
Biology, Assai (ed.) 1993.
[0196] The methods of the invention are also compatible with other
assay formats, including liposome immunoassays (LIA) (Rongen (1997) J.
Immunol. Methods 204:105-133), in which liposomes designed to bind
specific molecules (e.g., antibodies) and release encapsulated reagents
or markers are employed. The released chemicals can be detected using
standard techniques (see, e.g. Monroe (1986) Amer. Clin. Prod. Rev.
5:34).
[0197] b. Purification and Isolation
of mTERT and Telomerase Enzyme
[0198] The methods and reagents of the invention enable one to isolate
and purify the naturally occurring and recombinantly expressed murine
telomerase enzyme and mTERT protein of the invention from a variety of
sources, such as larval homogenates, bacterial cells, yeast, mammalian
cells, human cells, tissue culture media, transgenic plants and
animals, to substantial purity. For general information relating to
standard purification procedures, including selective precipitation
with such substances as ammonium sulfate; column chromatography,
immunopurification methods, and others see, for instance, Scopes, R.
K., Protein Purification: Principles and Practice, 2nd ed., Springer
Verlag, (1987), U.S. Pat. No. 4,673,641, Ausubel, and Sambrook. The
purification of TERT polypeptides is described herein and in related
applications. The purification of telomerase enzyme from a natural
source is also described in co-pending U.S. Ser. No. 08/833,377, filed
Apr. 4, 1997. The present invention also provides improvements to such
methods relating to antibodies against mTERT for purification, as well
as fusion proteins comprising a mTERT protein and a label that aids
purification.
[0199] i. Isolation of mTERT from
Bacterial Cultures
[0200] The present invention provides secreted recombinant mTERT
proteins which can isolated from the broth in which bacterial or
eukaryote cells have been cultured. In one embodiment, the
mTERT-encoding nucleic acids of the invention can be expressed as a
fusion protein with maltose-binding protein (MBP) or other proteins or
peptides fused thereto to increase the amount of secreted and soluble
product (see Chames (1997) FEBS Lett. 405:224-228); Sagiya (1994) Appl.
Microbio.l Biotechnol. 42:358-363).
[0201] ii. Purification of mTERT from
Bacterial Cells
[0202] When recombinant mTERT protein is expressed in bacteria, such as
E. coli, the protein may be exported into the periplasm of the
bacteria. The periplasmic fraction of the bacteria can be isolated by
cold osmotic shock or by other methods known to skill in the art; see
Ausubel (1970) J. Biol. Chem. 245:4842; Blight (1994) Curr. Opin.
Biotechnol. 5:468-474. For example, to isolate proteins from the
periplasm, the cells are centrifuged to form a pellet. The pellet can
be resuspended in a buffer containing, for example, 20% sucrose. To
lyse the cells, cells can be treated as described below. The suspension
can be centrifuged and the supernatant decanted and saved. The proteins
present in the supernatant can be separated and purified as described
herein.
[0203] iii. Purification of mTERT from
Inclusion Bodies
[0204] When recombinant mTERT and other telomerase enzyme proteins are
expressed by transformed bacteria or other cells in large amounts, the
proteins can form insoluble aggregates. Purification of aggregate
proteins, i.e., inclusion bodies, typically involves extraction,
separation and purification by disruption of the cells, typically but
not limited by, incubation in a buffer of about 100-150 [mu]g/mL
lysozyme and 0.1% NONIDET P40 a non-ionic detergent. The cell
suspension can be ground using a Polytron grinder (Brinkman
Instruments, Westbury, N.Y.). Alternatively, the cells can be sonicated
on ice. Alternate methods of lysing bacteria are described in Ausubel
and Sambrook and will be apparent to those of skill in the art.
[0205] The cell suspension is centrifuged and the pellet containing the
inclusion bodies resuspended in buffer, e.g., 20 mM Tris-HCl (pH 7.2),
1 mM EDTA, 150 mM NaCl and 2% TRITON-X 100, a non-ionic detergent. The
wash step may be repeated to remove more cellular debris. The remaining
pellet of inclusion bodies may be resuspended in an appropriate buffer
(e.g., 20 mM sodium phosphate, pH 6.8, 150 mM NaCl). Other appropriate
buffers will be apparent to those of skill in the art. Following the
washing step, the inclusion bodies can be solubilized by the addition
of a solvent that is both a strong hydrogen acceptor and a strong
hydrogen donor (or a combination of solvents each having one of these
properties) together with a reducing agent such as DTT. The proteins
that formed the inclusion bodies can then be renatured by dilution or
dialysis with a compatible buffer. Suitable solvents include, but are
not limited to, urea (typically from about 4 M to about 8 M), formamide
(typically at least about 80%, volume/volume basis), and guanidine
hydrochloride (typically from about 4 M to about 8 M). Some solvents
capable of solubilizing aggregate-forming proteins include, e.g., SDS
(sodium dodecyl sulfate), 70% formic acid, but may be inappropriate if
irreversible denaturation of the proteins occurs, which is typically
accompanied by a lack of immunogenicity and/or activity. Although
guanidine hydrochloride and similar agents are denaturants, this
denaturation is not irreversible and renaturation may occur upon
removal (by dialysis, for example) or dilution of the denaturant,
allowing re-formation of immunologically and/or biologically active
protein. The protein can be separated during or after solubilization
from other bacterial or other contaminating host proteins by standard
separation techniques using the reagents of the invention in accordance
with the methods of the invention.
[0206] iv. Standard Protein Separation
Techniques
[0207] The present invention can provides methods for purifying
telomerase enzyme and mTERT from a natural source or as a recombinant
protein from transformed cells or transgenic animals. The novel
reagents of the invention, such as the anti-mTERT antibodies, can be
used to improve purification procedures, such as those described in
co-pending U.S. Ser. No. 08/833,377, filed Apr. 4, 1997. Some
illustrative examples of methods for purifying murine telomerase
enzyme, mTERT, and other compositions used in the methods of the
invention are described below.
[0208] (1) Solubility Fractionation
[0209] If the protein mixture is complex, an initial salt fractionation
can separate many of the unwanted host cell proteins (or proteins
derived from the cell culture media) from the protein of interest. The
preferred salt is ammonium sulfate. Ammonium sulfate precipitates
proteins by effectively reducing the amount of water in the protein
mixture. Proteins then precipitate on the basis of their solubility.
The more hydrophobic a protein is, the more likely it is to precipitate
at lower ammonium sulfate concentrations, a typical protocol is to add
saturated ammonium sulfate to a protein solution so that the resultant
ammonium sulfate concentration is between 20-30%. This will precipitate
the most hydrophobic of proteins. The precipitate is discarded (unless
the protein of interest is hydrophobic), and ammonium sulfate is added
to the supernatant to a concentration known to precipitate the protein
of interest. The precipitate is then solubilized in buffer and the
excess salt removed if necessary, either through dialysis or
diafiltration. Other methods that rely on solubility of proteins, such
as cold ethanol precipitation, are well known to those of skill in the
art and can be used to fractionate complex protein mixtures.
[0210] (2) Size Differential Filtration
[0211] If the size of the protein of interest is known or can be
estimated from the cDNA sequence, proteins of greater and lesser size
can be removed by ultrafiltration through membranes of different pore
size (e.g., Amicon or Millipore membranes). As a first step, the
protein mixture is ultrafiltered through a membrane with a pore size
that has a lower molecular weight cut-off than the molecular weight of
the protein of interest. The retentate of the ultrafiltration is then
ultrafiltered against a membrane with a molecular cut off greater than
the molecular weight of the protein of interest. The protein will pass
through the membrane into the filtrate. The filtrate can then be
chromatographed.
[0212] (3) Column Chromatography
[0213] Proteins can be separated on the basis of their size, net
surface charge, hydrophobicity and affinity for ligands. In addition,
antibodies raised against proteins can be conjugated to column matrices
and the proteins immunopurified. All of these general methods are well
known in the art. See Scopes (1987) supra. Chromatographic techniques
can be performed at any scale and using equipment from many different
manufacturers (e.g., Pharmacia Biotech). Protein concentrations can be
determined using any technique, e.g., as in Bradford (1976) Anal.
Biochem. 72:248-257.
[0214] v. Isolation of mTERT and
Murine Telomerase Enzyme
[0215] Telomerase can be isolated and purified by any of a variety of
means provided by the invention, as described above. In one embodiment
of the invention, telomerase enzyme can be purified to over 60,000-fold
purity over cytoplasmic crude cell preparations. The steps to be
included in a purification method depend on the level of purification
one desires. An illustrative method to purify telomerase enzyme or
mTERT protein from an impure composition containing organic
biomolecules to at least 60,000-fold compared to crude extract (about
4% relative purity) can involve, e.g., (1) contacting the mTERT with a
first matrix that binds molecules bearing a negative charge, for
example, POROS 50 HQ, separating mTERT from other organic biomolecules
that do not bind to the matrix and collecting the mTERT; (2) contacting
the mTERT with a matrix that binds molecules bearing a positive charge,
for example POROS Heparin 20 HE-1, and separating mTERT from other
organic biomolecules that do not bind to the matrix and collecting the
mTERT; (3) contacting the mTERT with a second matrix that binds
molecules bearing a negative charge, e.g., SOURCE 15Q, separating mTERT
from other organic biomolecules that do not bind to the matrix and
collecting the mTERT; (4) contacting the mTERT with an affinity agent
having specific affinity for mTERT, e.g., an oligonucleotide
complementary to the telomerase enzyme's RNA moiety or an anti-mTERT
antibody, separating mTERT from other organic biomolecules that do not
bind to the affinity agent and collecting the mTERT; and/or (5)
separating the mTERT from other organic biomolecules according to
molecular size, shape, or buoyant density, e.g., separating molecules
according to size on a TosoHaas TSK-gel*G5000PWXL sizing column and
collecting the mTERT. The isolation and purification protocol also can
include the step of contacting the mTERT with an
intermediate-selectivity matrix, separating mTERT from other organic
biomolecules that do not bind to the intermediate-selectivity matrix
and collecting the mTERT, preferably before the affinity step. mTERT
can be isolated to different levels of purity by altering, changing the
sequence of, or eliminating any of the steps in the purification
protocol. However, any preferred protocol will typically include
contacting the mTERT with an affinity agent, such as the antibodies of
the invention. Contacting the mTERT with at least one matrix that binds
molecules bearing a negative charge or a positive charge is the next
preferred step or steps to include in the protocol.
[0216] c. Amino Acid Sequence
Determination
[0217] Illustrative amino acid sequences of mTERT of this invention can
be determined by, for example, Edman degradation, a technique which is
well known in the art. In addition to the internal sequencing (see also
Hwang (1996) J. Chromatogr. B. Biomed. Appl. 686:165-175), N-terminal
sequencing can be performed by techniques known in the art. For
C-terminal sequence determination, a chemical procedure for the
degradation of peptides and analysis by
matrix-assisted-laser-desorption ionization mass spectrometry
(MALDI-MS) can be used, see, e.g., Thiede (1997) Eur. J. Biochem.
244:750-754.
[0218] d. Molecular Weight/Isoelectric
Point Determination
[0219] The molecular weight of a protein can be determined by many
different methods, all known to one of skill in the art. Some methods
of determination include: SDS gel electrophoresis, native gel
electrophoresis, molecular exclusion chromatography, zonal
centrifugation, mass spectroscopy, and calculation from sequencing.
Disparity between results of different techniques can be due to factors
inherent in the technique. For example, native gel electrophoresis,
molecular exclusion chromatography and zonal centrifugation depend on
the size of the protein. The proteins that are cysteine rich can form
many disulfide bonds, both intra- and intermolecular. Mobility under
SDS gel electrophoresis conditions depends on the binding of SDS to
amino acids present in the protein. Some amino acids bind SDS more
tightly than others, therefore, proteins will migrate differently
depending on their amino acid composition. Mass spectroscopy and
calculated molecular weight from the sequence in part depend upon the
frequency that particular amino acids are present in the protein and
the molecular weight of the particular amino acid. If a protein is
glycosylated, mass spectroscopy results will reflect the glycosylation
but a calculated molecular weight may not.
[0220] The calculated molecular weight of mTERT (SEQ ID NO:2), with a
calculated length of 1122amino acids, is estimated to be about 127 kD
(specifically, 127,979 kD); and its apparent molecular weight by SDS
gel electrophoresis is estimated to be between about 115 kD to about
140 kD. However, additional mTERT proteins, mTERT isoforms, alleles and
homologues within the scope of the invention are not limited to this
molecular weight range.
[0221] The isoelectric point of a protein can be determined by native
gel (or disc) electrophoresis, isoelectric focussing or, in a preferred
method, by calculation given the amino acid content of the protein
(see, e.g., Wehr (1996) Methods Enzymol. 270:358-374; Moorhouse (1995)
J. Chromatogr. a. 717:61-69, describing capillary isoelectric
focusing). The isoelectric point (pI) of mTERT (SEQ ID NO:2) has been
calculated to be about 10.4. However, mTERT alleles, isoforms and
homologues, within the scope of the invention are not limited to this
range of isoelectric points.
[0222] e. mTERT Fusion Proteins
[0223] The mTERT of the invention can also be expressed as a
recombinant protein with one or more additional polypeptide domains
linked thereto to facilitate protein detection, purification, or other
applications. Such detection- and purification-facilitating domains
include, but are not limited to, metal chelating peptides such as
polyhistidine tracts and histidine-tryptophan modules that allow
purification on immobilized metals, protein a domains that allow
purification on immobilized immunoglobulin, and the domain utilized in
the FLAGS extension/affinity purification system (Immunex Corp, Seattle
Wash.). The inclusion of a cleavable linker sequences such as Factor Xa
or enterokinase (Invitrogen, San Diego Calif.) between the purification
domain and telomerase or telomerase-associated protein(s) may be useful
to facilitate purification. One such expression vector provides for
expression of a fusion protein comprising the sequence encoding an
mTERT of the invention and nucleic acid sequence encoding six histidine
residues followed by thioredoxin and an enterokinase cleavage site
(e.g., see Williams (1995) Biochemistry 34:1787-1797). The histidine
residues facilitate detection and purification while the enterokinase
cleavage site provides a means for purifying the desired protein(s)
from the remainder of the fusion protein. Technology pertaining to
vectors encoding fusion proteins and applications of fusion proteins
are well described in the patent and scientific literature, see e.g.,
Kroll (1993) DNA Cell. Biol., 12:441-53.
3. Assaying for Telomerase Activity
[0224] The assays described below can be used to detect, assess the
purity of and quantify isolated or recombinant mTERT produced in
bacteria, insect and yeast, tissue culture fluid and plant and animal
tissues, or other, including natural, sources. The activity assays
described below and provided by the present invention can be used to
identify compositions which modulate mTERT, i.e., modify, activate or
inhibit, the activity of telomerase, ie., act as antagonists or
agonists of telomerase-mediated DNA replication.
[0225] a. Measuring an Increase or
Decrease in the Length of Telomeres
[0226] Because telomerase enzyme extends telomerase DNA, and because
telomeres shorten as cells divide in the absence of telomerase, one can
indirectly detect mTERT or telomerase enzyme by measuring telomere
length. Assays well known in the art that can be used to determine the
length of telomeres include restriction endonuclease digestion and
probing as well as a modified Maxam-Gilbert reaction, see e.g., WO
93/23572; WO 95/13382; WO 96/41016; U.S. Pat. Nos. 5,645,986;
5,707,795; and 5,686,245.
[0227] Direct fluorescence in situ by fluorochrome-labeled nucleic acid
probes enables determination of the presence and location of DNA
sequences complementary to the labeled probe. Without further
amplification, this method can be limited to detecting targets with
middle to high copy numbers. However, both signal and target
amplification is possible, for example, with labeled antibody (as a
fluorochrome) specific for a label which is covalently attached to the
nucleic acid probe, as discussed above; also, see Schwarzacher (1994)
"Direct fluorochrome-labeled DNA probes for direct fluorescent in situ
hybridization to chromosomes" Methods Mol. Biol. 28:167-176.
[0228] In one embodiment of the invention, telomerase enzyme-generated
products or telomeric structures are detected using a variation of an
antibody amplification technique, the so-called catalyzed signal
amplification (CSA) technique. This immunohistochemical assay allows in
situ visualization of the telomere (or any composition) of interest. In
one variation, incubation with primary antibody is followed by
secondary antibody conjugated to biotin, followed by a
strepavidin-biotin-peroxidase complex, biotinyl-tyramide reagent and
3,3'-diaminobenzidine tetrahydrochloride (see Sanno (1996) Am. J. Clin.
Pathol. 106:16-21; Sanno (1997) Neuroendocrinology 65:299-306).
[0229] b. In Vitro Telomerase Activity
Assays
[0230] In one embodiment, the mTERT protein of the invention is used to
reconstitute telomerase activity. Such reconstitution is useful not
only for detecting modulators of telomerase-mediated DNA replication in
in vitro activity assays, but also for identifying mTERT polypeptides
and telomerase enzymes, including mTERT isoforms, alleles and
homologues.
[0231] i. Detecting Telomerase
Activity Using Immobilized Enzyme
[0232] In one embodiment of the invention, telomerase activity is
monitored in a solid-phase system using the so-called catalyzed
reporter deposition (CARD) system. Telomerase enzyme or mTERT is
immobilized onto a solid phase using the antibodies of the invention or
chemical linkers, and the like. To assay fill or a "partial" mTERT or
telomerase enzyme activity, a telomerase enzymatic reaction is carried
out in a buffered aqueous solution compatible with the assayed
telomerase activity. The appropriate reagents are added to detect the
activity, for example, to allow the telomerase to catalyze multiple
copies of detectable, reaction product. For general information, see
Bobrow (1992) "The use of catalyzed reporter deposition as a means of
signal amplification in a variety of formats" J. Immunol. Methods
150:145-149; and Schmidt (1997) "Signal amplification in the detection
of single-copy DNA and RNA by enzyme-catalyzed deposition (CARD) of the
novel fluorescent reporter substrate Cy3.29-tyramide" J. Histochem.
Cytochem 45:365-373.
[0233] c. Incorporation of Labeled
Nucleotides-Primer Extension
[0234] One method which assays for telomerase activity in cell samples
relies on the incorporation of radioactively or otherwise labeled
nucleotides into newly synthesized polynucleotides by elongation of a
telomerase substrate, i.e., the telomerase extension product. Briefly,
this assay measures the amount of nucleotides incorporated into
polynucleotides synthesized on a primer sequence. The amount
incorporated is typically measured as a function of the intensity of a
band on a phosphor screen, such as the PhosphorImager(R) or
FluorImager(R) (Molecular Dynamics, Sunnyvale, Calif.) exposed to a gel
on which the radioactive products are separated. See Morin (1989) Cell
59:521-529.
[0235] Conventional "primer extension" assays use an oligonucleotide
substrate, a radioactive deoxyribonucleotide triphosphate (dNTP) for
labeling the extended substrate, and gel electrophoresis for resolution
and display of telomerase extension products. Because telomerase stalls
and can release the DNA after adding the first G in the 5'-TTAGGG-3'
(SEQ ID NO:7) telomeric repeat, the characteristic pattern of products
detected on the gel is a six nucleotide ladder of extended
oligonucleotide substrates. The phase of the repeat depends on the 3'
end sequence of the substrate; telomerase recognizes where the end is
in the repeat and synthesizes accordingly to yield contiguous,
repetitive sequences. As noted above, the nucleotides, substrate, and
extended substrate can be alternatively labeled with non-radioactive
means such as fluorescent, phosphorescent, or chemiluminescent labels.
The nucleotides or extended substrate can be "tagged," where the "tag"
can be identified by a second labeled molecule. For example, the tag
can be biotin. The resultant tagged nucleotide can be recognized by
using a labeled avidin, such as avidinylated horseradish peroxidase,
followed by a chromogenic substrate, as, e.g., in Durrant (1996) Mol.
Biotechnol. 6:65-67. Many variations on these detection formats are
well known in the art.
[0236] i. Dot Blot Assay
[0237] Another assay for telomerase activity is the dot blot assay. The
dot blot assay is useful for routine screening because it can be used
in high throughput mode, and hundreds of assays can be carried out in a
single day with a good portion of the labor performed automatically.
The dot blot assay is most effective for comparing activity of samples
at roughly the same level of purity and is less effective for a
multiplicity of samples at different stages of purity, and so may not
be a preferred assay for determining relative purity. See co-pending
U.S. Ser. No. 08/833,377, filed Apr. 4, 1997.
[0238] ii. Reverse Transcription
PCR/Quantitative PCR
[0239] The present invention provides polymerase chain reaction (PCR)
assays that can be used to detect and quantify levels of telomerase
enzyme-generated product. See also, U.S. Pat. No. 5,629,154. Other
target amplification techniques can also be employed in these methods,
and one of skill in the art will appreciate that, whatever
amplification method is used, if a quantitative result is desired, care
must be taken to use a method that maintains or controls for the
relative amplification of the various nucleic acids amplified. PCR is
discussed in general above, a comprehensive discussion on quantitative
PCR can be found in the scientific and patent literature, and is, for
example, outlined in Innis, supra; see also Okamoto (1997) Biol. Pharm.
Bull. 20:1013-1016.
[0240] iii. Telomeric Repeat
Amplification Protocol (TRAP Assay)
[0241] The invention also provides for novel embodiments of the TRAP
assay and variations of this well known telomerase activity assay. The
present invention provides reagents useful for the TRAP assay as well
as new amplification based telomerase activity assays for a wide
variety of applications.
[0242] One limitation of the primer extension assay, described above,
for assessing telomerase activity is weak signal strength, often
necessitating long (7 or more days) autoradiographic exposure.
Fortunately, the highly sensitive PCR-based "TRAP" assay for measuring
telomerase activity has been developed. The TRAP assay is an
amplification-based method for detecting, determining, and measuring
telomerase activity and is described in PCT Publication Nos. WO
97/15687 and WO 95/13381 and U.S. Pat. No. 5,629,154; see also U.S.
Ser. No. 08/632,662, and U.S. Ser. No. 08/631,554, filed 15 Apr. 1996
and 12 Apr. 1996, respectively. See also, Kim (1994) Science 266:2011;
PCT/US96/09669; Piatyszek (1995) Methods in Cell Science 17:1-15; Krupp
(1997) Nuc. Acids Res. 25:919-921; Kim (1994) Science 266:2011-2015;
Wright (1995) Nucleic Acids Res. 23 :3794-3795; Tatematsu (1996)
Oncogene 13:2265-2274; and Kim (1997) Nuc. Acids Res. 25:2595-2597.
[0243] The TRAP assay allows one to measure the elongation of a short
oligonucleotide primer known to act as an efficient substrate of
telomerase enzyme. Telomerase is an RNA-dependent DNA polymerase that
normally synthesizes telomeric repeats at the 3' end of the leading DNA
strand. mTERC and hTERC can function as templates for the extension of
a chromosomal end. hTERT synthesizes telomeric repeats (TTAGGG)n (SEQ
ID NO:7) onto the 3' end of a telomerase substrate oligonucleotide
("TS"), 5'-AATCCGTCGAGCAGAGTT-3' (SEQ ID NO:6). Although the TS
sequence lacks TTAGGG (SEQ ID NO:7) repeats, it is a good human
telomerase enzyme substrate (first described in Morin, (1991) Nature
353:454-456). The TS substrate lacks TTAGGG repeats, allowing for
forward PCR amplification primers specific for extended TS. The
forward, or other primer of the primer pair anneals only to the TTAGG
(SEQ ID NO:7) repeats added by the telomerase to TS, and that primer
pair enables efficient amplification of the extended TS. mTERT activity
can be assayed using this TRAP model, as demonstrated in the Example,
below.
[0244] For use of internal controls in TRAP assays, see the
publications cited supra and, e.g., Yashima (1997) "Telomerase activity
and in situ telomerase RNA expression in malignant and non-malignant
lymph nodes" J. Clin Pathol 50:110-117.
[0245] iv. Reconstitution of Activity
In Vitro
[0246] In one embodiment of the invention, using mTERT encoding nucleic
acid, telomerase enzyme activity, full or "partial," is reconstituted
in vitro in an appropriate in vitro translation or
transcription/translation system, many of which are commercially
available, e.g., RiboMAX(TM) Large Scale RNA Production System, Flexi
Rabbit Reticulocyte Lysate System, Promega Corp., Madison, Wis. In
alternative embodiments, the RNA component of the mTERT-containing
telomerase enzyme complex can be mTERC or hTERC: Other
telomerase-associated proteins can also be co-expressed in the system.
[0247] d. In Vivo/In Situ Telomerase
Activity Assays-Reconstitution of Activity
[0248] The present invention provides methods for identifying
modulators of mTERT-containing telomerase enzyme-mediated DNA
replication by in vitro, in vivo and in situ activity assays. Methods
for identifying modulators of telomerase activity have been described.
See, e.g., U.S. Pat. No. 5,645,986; and Ser. No. 08/288,501, filed Aug.
10, 1994. The present invention provides improvements to these known
methods by providing highly purified murine telomerase enzyme, mTERT,
as well as anti-mTERT antibodies for use as controls or agents. The
present invention also provides activity assays that can identify
modulators of full or a partial activity of mTERT or telomerase enzyme.
[0249] In certain embodiments, assay formats are chosen that detect the
presence, absence or abundance of either a telomerase enzyme or mTERT
protein, a telomerase- or mTERT-generated product, an mTERT isoform,
allele, or homologue, in each cell in a sample or in a representative
sampling. Examples of such formats include those that detect a signal
by histology, e.g., immunohistochemistry, and with nucleic acids,
either including signal-enhancing steps, such as in situ nucleic acid
amplification followed by fluorescence-activated cell sorting
(FACS-PCR). These formats are particularly advantageous when dealing
with a highly heterogeneous cell population, e.g., containing multiple
cell types from among which only one or a few types have elevated mTERT
levels.
[0250] In vivo assays include non-human cell systems into which
recombinant mTERT is expressed. The RNA moieties mTERC or hTERC can
either be simultaneously co-expressed with mTERT or hTERT to generate
telomerase enzyme activity. Other murine telomerase-associated proteins
can also be co-expressed in this in vivo assay system. This
reconstitution of full or "partial" telomerase activity using mTERT in
vivo provides for a method of screening for telomerase modulators in
cells or animals from any origin. Telomere length can also be measured,
as described above.
[0251] Telomerase enzyme antagonists that can cause or accelerate loss
of telomeric structure can be identified by monitoring and measuring
their effect on mTERT or telomerase enzyme activity in vivo, ex vivo,
or in vitro, or by their effects on telomeric length (as through
staining or use of tagged hybridization probes) or, simply, through
cell death of telomerase positive cancer cells (critical shortening of
telomeres leads to a phenomenon termed "crisis" or M2 senescence (Shay
(1991) Biochem. Biophys. Acta 1072:1-7), which cancer cells can bypass
by activating telomerase or another telomere length maintenance pathway
but which otherwise will lead to their death through chromosomal
deletion and rearrangement).
[0252] The present invention also provides assays that can also be used
to screen for agents that increase the full or a "partial" activity of
telomerase, either by causing TERT protein or telomerase to be
expressed in a cell in which it normally is not expressed or by
increasing telomerase activity levels in telomerase positive cells.
Such agonists can be identified in an activity assay of the invention
or by their effect on telomere length or both.
[0253] i. Administering
Telomerase-activity-modulators to Mortal Cells
[0254] In one embodiment, the invention provides recombinant mTERT and
mTERT-containing telomerase enzyme and necessary telomerase enzyme
complex components for expression in normal, diploid mortal cells to
create indefinitely proliferating cells, to immortalize those cells, or
to increase their proliferative capacity. For example, expression of
mTERT of the invention can be used to create immortal or indefinitely
proliferating B lymphocytes. In another embodiment, mortal cells that
produce a commercially desirable protein, such as pituitary cells, are
immortalized or made indefinitely proliferating by expression of an
mTERT, e.g., as that of SEQ ID NO:2.
[0255] In another embodiment, the invention provides means to inhibit
the expression or activity of telomerase enzyme in a cell to be used
for transplantation into a host so that the transplanted cell cannot
become immortalized or indefinitely proliferating. This method is ideal
for cells that have been modified to delete histocompatibility antigens
or modified in some way to prevent or decrease the possibility of
immune rejection, because such cells are preferred for transplantation.
Reintroduction of normal cells into an individual presents a risk that
the cells may change to a state of uncontrolled cell growth, becoming a
malignancy. The present invention prevents this complication by
"knocking out" or inhibiting (antagonizing) telomerase activity (or a
telomerase enzyme complex component necessary for activity). Without an
active telomerase, the cells are "irreversibly mortal," decreasing the
probability of malignant transformation after reintroduction.
[0256] When reconstituting telomerase activity in mortal cells, in
which telomerase activity normally cannot be detected, generation of a
maximum level of telomerase activity may necessitate co-expression of
mTERT with other components, especially such as mTERC, and in some
cases, other telomerase-associated proteins.
[0257] ii. Administering
Telomerase-activity-modulators to Immortal Cells
[0258] Antagonists of telomerase-mediated DNA replication can be
identified by administering the putative inhibitory composition to a
cell that is known to exhibit significant amounts of telomerase
activity, such as cancer cells or indefinitely proliferating cells.
Such compositions so identified can then be used to treat diseases,
such as cancer, that are exacerbated by or caused by or depend on a
minimum level of telomerase expression or activity. Telomerase
enzyme-positive cells can be tumor cell lines, isolated from in vivo
sources, or present in an intact animal, as for example, in a solid
tumor. Reconstitution of activity by the methods and with the reagents
of the invention in an in vitro system, cell or animal using mTERT,
mTERC, and/or other telomerase-associated components, allows one to
screen for antagonists by assaying or monitoring the expected decrease
in telomerase activity, or accelerated loss of telomeric length, or
senescence (cancer cells that continue to divide despite critical
telomere shortening die in the absence of telomerase activity).
[0259] iii. Transgenic Animals
Incorporating mTERT Genes
[0260] The introduction of mTERT or other TERT genes into mice to
create transgenic mice can be used to assess the consequences of
mutations or deletions to the coding or transcriptional regulatory
(e.g., promoter) regions. In one embodiment, the endogenous mTERT gene
in these mice is still functional and wild-type (native) telomerase
activity can still exist. With the use of a promoter that drives high
level expression of the exogenous TERT construct, the endogenously
produced mTERT protein can be competitively replaced with the
introduced, exogenous TERT protein. This transgenic animal (retaining a
functional endogenous telomerase activity) is preferred in situations
where it is desirable to retain "normal," endogenous telomerase
function and telomere structure.
[0261] In other situations, where it is desirable that all telomerase
activity is by the introduced exogenous TERT protein, use of an mTERT
knockout line (described below) is preferred.
[0262] Promoter function, and in a preferred embodiment, mTERT promoter
function, can be assessed with mTERT transgenic animals. Alterations of
mTERT promoters can be constructed that drive mTERT or a reporter gene
to assess their function and expression pattern and characteristics
(the invention also provides constructs and methods for gene expression
driven by an mTERT promoter by transient transfection). In one
embodiment, the ability of an mTERT promoter to limit the expression of
a cell killing gene (e.g., thymidine kinase or ricin) to cancer cells
can be assessed. The genomic regions that confer developmental and
tissue specific expression can be identified. This could lead to the
identification of proteins or other transcriptional trans-activators
that modulate gene, e.g., mTERT, expression. Proteins that modulate
mTERT expression are attractive targets for therapeutic intervention
either for inhibition of telomerase activity in cancer cells or for the
extension of replicative lifespan in normal cells and other uses as
described herein.
[0263] Transgenic animal or cells expressing mTERT proteins in an
inappropriate manner can also be constructed. Promoters can be used
that give constitutive expression in all tissues or developmental
stages or limit expression to specific cell types or tissues. In this
manner the biological consequences of an mTERT native or altered
protein can be assessed in vivo or ex vivo.
[0264] Transgenic animals or cells expressing mutant (i.e., non-native)
mTERT proteins can also be constructed. This will provide an in vivo or
ex vivo model system to assess the structure and function of mTERT
amino acid sequences on telomerase or telomere function.
[0265] iii. Telomerase Knockout Cells
and Animal Models
[0266] The invention also includes "knockout" cells and animals, in
which one or several units of the endogenous telomerase enzyme complex
have been deleted, altered, or inhibited. These "knockout" cells and
animals can serve as a model useful in drug discovery and development,
and include modified cells or animals with increased amounts of
endogenous, modified endogenous or exogenous telomerase enzyme
activity. Reconstitution of telomerase activity can save the cell or
animal from the inevitable cell death caused by inability to maintain
telomeres.
[0267] Methods of altering the expression of endogenous genes are well
known to those of skill in the art. Typically, such methods involve
altering or replacing all or a portion of the regulatory sequences
controlling expression of the particular gene to be regulated The
regulatory sequences, e.g., the native promoter can be altered. One
technique for targeted mutation of genes involves placing a genomic DNA
fragment containing the gene of interest into a construct, i.e., a
vector. An example of such a vector includes the cloning of two genomic
regions flanking the gene of interest around a selectable
neomycin-resistance cassette in a vector containing a thymidine kinase
gene. See also Westphal (1997) Curr. Biol. 7:530-533. This "knock-out"
construct is then transfected into the appropriate host cell, ie., a
mouse embryonic stem (ES) cell, as discussed in detail above.
[0268] e. Quantitation of Telomerase
Activity
[0269] Telomerase enzyme activity can be quantified in a variety of
ways, depending on the method of measurement and convenience.
Telomerase activity can be expressed in terms of the amount of mTERT,
telomerase enzyme or telomerase-generated product in a sample, which
can be expressed as standard units of weight per quantity of biological
sample (e.g., picograms per gram tissue, picograms per number of cells,
etc.), as a number of molecules per quantity of biological sample
(e.g., molecules/cell, moles/cell, etc.) or some similar method, or may
be expressed using arbitrary units (e.g., comparing a normal cells from
an individual to indefinitely proliferating or immortal, cancer cells).
The quantity of mTERT, telomerase enzyme or telomerase-generated
product can also be expressed in relation to the quantity of another
molecule, ie., the number of mTERT molecules (of gene, protein or mRNA
transcript) per sample per number of 28S rRNA transcripts in sample;
nanograms of mTERT protein per nanograms of actin, and the like.
[0270] When measuring mTERT, telomerase or telomerase-generated product
in two (or more) different samples, it will sometimes be useful to have
a common basis of comparison of the two samples. When comparing a
sample of normal tissue and a sample of cancerous tissue, equal amounts
of tissue (by weight, volume, number of cells, etc.) can be compared.
Alternatively, equivalents of a marker molecule (e.g., 28S rRNA, mTERC,
actin) may be used. For example, the amount of telomerase or
telomerase-generated product in a healthy tissue sample containing 10
picograms of 28S rRNA can be compared to a sample of tissue containing
the same amount of 28S rRNA.
[0271] In certain embodiments, assay formats are chosen that detect the
abundance of an mTERT isoform, allele or homologue in each cell in a
sample in situ. Examples of such formats include those that detect the
intensity of a signal by immuno-histochemistry with nucleic acid
signal-enhancing steps, such as in situ nucleic acid amplification
followed by fluorescence-activated cell sorting (FACS-PCR). These
formats are particularly advantageous when dealing with a highly
heterogeneous cell population, e.g., containing multiple cells types or
which only one or a few types have elevated mTERT levels. General
methodology related to this technique is described in Cao (1995)
"Identification of malignant cells in multiple myeloma bone marrow with
immunoglobulin VH gene probes by fluorescent in situ hybridization and
flow cytometry" J. Clin. Invest. 95:964-972.
[0272] It is not always necessary to quantify mTERT mRNA or protein or
to detect a full or partial telomerase enzyme activity. Often the
detection of an mTERT gene product will be sufficient for a diagnosis,
as under assay conditions in which the telomerase activity or
telomerase-generated product is not detectable in control, e.g.,
nonmalignant, normal cells. As another example, when the levels of
product found in a test (e.g., tumor) and control (e.g., mortal cell)
samples are directly compared, quantitation of mTERT is not necessary
to make an accurate determination.
[0273] i. Quantitating Amounts of
Nucleic Acid in a Sample to Determine Telomerase Activity: Methodologies
[0274] Telomerase enzyme activity can be expressed in terms of the
amount of telomerase-generated product in a sample, i.e., the amount of
telomere DNA synthesized by the enzyme complex. Quantitation of RNA is
also useful for determining the transcriptional efficiency of
recombinant DNA in expression systems, such as with in vitro
transcription, antisense RNA expression, transfection of mortal,
indefinitely proliferating or immortal cells and transgenic animals.*
Evaluating levels of RNA is also useful in evaluating cis- or
trans-transcriptional regulators.
[0275] General techniques for quantitating amount of nucleic acids in
samples are well known in the art, as are described, e.g., see Diaco in
Innis (1995) PCR Strategies, supra, "Practical Considerations for the
design of quantitative PCR assays", pg. 84-108. Branched DNA signal
amplification is described in Urdea (1994) Bio/Tech. 12:926, and U.S.
Pat. No. 5,124,246.
[0276] f. Partial Activity Telomerase
Assays
[0277] In one embodiment of the invention, a variety of partial
activity telomerase assays are provided to identify a variety of
different classes of modulators of telomerase activity. The "partial
activity" assays of the invention allow identification of classes of
telomerase activity modulators that might otherwise not be detected in
a "full activity" telomerase assay. One partial activity assay involves
the non-processive activity of mTERT and telomerase enzyme. The
processive nature of telomerase activity is described by Morin (1989)
supra; see also Prowse (1993) "Identification of a nonprocessive
telomerase activity from mouse cells" Proc. Natl. Acad. Sci. USA
90:1493-1497. Another partial activity assay of the invention exploits
the "reverse-transcriptase-like" activity of telomerase. In these
assays, one assays the reverse transcriptase activity of the mTERT
protein or telomerase enzyme. See Lingner (1997) "Reverse transcriptase
motifs in the catalytic subunit of telomerase" Science 276:561-567.
Another partial activity assay of the invention exploits the
"nucleolytic activity" of mTERT and telomerase enzyme, involving the
enzyme's removing of at least one guanine "G" residue from the 3'
strand. This nucleolytic activity has been observed in the Tetrahymena
telomerase by Collins (1993) "Tetrahymena telomerase catalyzes
nucleolytic cleavage and nonprocessive elongation" Genes Dev
7:1364-1376. Another partial activity assay of the invention involves
analyzing mTERT's and telomerase enzyme's ability to bind nucleotides
as part of its enzymatically processive DNA polymerization activity.
Another partial activity assay of the invention involves analyzing
mTERT's or telomerase enzyme's ability to bind its RNA moiety, ie.,
mTERC, used as a template for telomere synthesis.
[0278] Additional partial activity assays of the invention involve
analyzing mTERT's and telomerase enzymes's ability to bind chromosomes
in vivo, or to bind oligonucleotide primers in vitro or in
reconstituted systems, or to bind proteins associated with chromosomal
structure (see, for an example of such a protein, Harrington (1995) J
Biol Chem 270: 8893-8901). Chromosomal structures which bind mTERT
include, for example, telomeric repeat DNA, histones, nuclear matrix
protein, cell division/cell cycle control proteins and the like. One of
skill in the art can use the methods of the invention to identify which
portions (e.g., domains) of these telomerase-associating proteins
contact telomerase. In one embodiment of the invention, these
TERT-binding and telomerase-associating proteins or fragments thereof
are used as modulators of telomerase activity.
4. Modulators of Telomerase Activity
[0279] The invention provides methods and reagents for screening for
compositions or compounds capable of modifying the ability of mTERT and
mTERT-containing telomerase enzyme to synthesize telomere DNA ("full
activity"). The invention also screens for modulators of any or all of
mTERT's "partial activities," some of which are described above. In
various embodiments, the invention includes, but is not limited to,
screening for antagonists that: bind to mTERT's active site; inhibit
the association of its RNA moiety, telomerase-associated proteins,
nucleotides, or telomeric DNA to the telomerase enzyme or mTERT
protein; promote the disassociation of the enzyme complex; or inhibit
any of the "partial activities" described above.
[0280] Screening for antagonist activity provides for compositions that
decrease telomerase enzyme activity, thereby preventing unlimited cell
division of cells exhibiting unregulated cell growth, such as cancer
cells. Telomerase enzyme activity has been identified as an important
cancer marker, one whose levels can diagnose, prognose, and predict the
outcome or seriousness of disease, as described in U.S. Pat. Nos.
5,489,508; 5,648,125; and 5,639,613. The present invention provides
mTERT antagonists which can also inhibit the activity of hTERT, or can
serve as a structural basis for developing hTERT antagonists, thus
providing useful reagents for treating cancer by modulating telomerase
activity.
[0281] Screening for agonist activity provides for compositions that
increase telomerase's activity in a cell. Such agonist compositions
provide for methods of creating a state of continuous proliferation or
immortalizing otherwise normal, untransformed cells, including cells
which can express useful proteins, as discussed above. Such agonists
also provide for methods of controlling or delaying cellular
senescence. The present invention provides mTERT agonists which can
also increase the activity of hTERT, or can serve as a structural basis
for developing hTERT agonists.
[0282] The methods of the invention are amenable to adaptations from
protocols described in the scientific and patent literature and known
in the art. For example, when a telomerase enzyme or mTERT protein of
this invention is used to identify compositions which act as modulators
of telomerase enzyme activities, large numbers of potentially useful
molecules can be screened in a single test. The modulators can have an
inhibitory (antagonist) or potentiating (agonist) effect on telomerase
activity. For example, if a panel of 1,000 inhibitors is to be
screened, all 1,000 inhibitors can potentially be placed into one
microtiter well and tested simultaneously. If such an inhibitor is
discovered, then the pool of 1,000 can be subdivided into 10 pools of
100 and the process repeated until an individual inhibitor is
identified.
[0283] a. Synthetic Small Molecule
Modulators
[0284] Potential modifiers of telomerase activity, i.e., test
compounds, preferably of molecular weight under about 10,000 daltons;
more preferably, under about 5,000 daltons; and most preferably, under
about 500 daltons, include synthetic molecules, which can be designed
and produced for testing by any technique, many of which are described
in the patent and scientific literature, and a few illustrative
examples are described below.
[0285] i. Combinatorial Chemistry
Methodology
[0286] The creation and simultaneous screening of large libraries of
synthetic molecules can be carried out using well-known techniques in
combinatorial chemistry, e.g., see van Breemen (1997) Anal. Chem.
69:2159-2164; Lam (1997) Anticancer Drug Des. 12:145-167 (1997); Shipps
(1997) Proc. Natl. Acad. Sci. USA 94:11833-11838; Kaur (1997) J.
Protein Chem. 16:505-511; Zhao (1997) J. Med. Chem. 40:4006-4012, for
screening solution-phase combinatorial libraries using pulsed
ultrafiltration/electrospray mass spectrometry.
[0287] ii. Rational Drug Design
[0288] Rational drug design involves an integrated set of methodologies
that include structural analysis of target molecules, synthetic
chemistries, and advanced computational tools. When used to design
modulators, such as antagonists/inhibitors of protein targets, such as
mTERT protein and mTERT-containing telomerase enzyme, the objective of
rational drug design is to understand a molecule's three-dimensional
shape and chemistry. Rational drug design is aided by X-ray
crystallographic data or NMR data, which can now be determined for the
mTERT protein and telomerase enzyme in accordance with the methods and
using the reagents provided by the invention. Calculations on
electrostatics, hydrophobicities and solvent accessibility are also
helpful. See, e.g., Coldren (1997) Proc. Natl. Acad. Sci. USA
94:6635-6640.
[0289] b. Inhibitory (Antagonist) and
Activator (Agonist) Peptide Modulators
[0290] Potential modulators of mTERT and telomerase enzyme activity
also include peptides. For example, oligopeptides with randomly
generated sequences can be screened to discover peptide modulators
(agonists or inhibitors) of mTERT and/or telomerase activity. Such
peptides can be used directly as drugs or to find the orientation or
position of a functional group that can inhibit telomerase activity
that, in turn, leads to design and testing of a small molecule
inhibitor. Peptides can be structural mimetics, and one can use
molecular modeling programs to design mimetics based on the
characteristic secondary structure and/or tertiary structure of
telomerase enzyme and mTERT protein. Such structural mimetics can also
be used therapeutically, in vivo, as modulators of telomerase activity
(agonists and antagonists). Structural mimetics can also be used as
immunogens to elicit anti-mTERT protein antibodies.
[0291] c. Inhibitory Natural Compounds
as Modulators of Telomerase Activity
[0292] In addition, a large number of potentially useful
activity-modifying compounds can be screened in extracts from natural
products as a source material. Sources of such extracts can be from a
large number of species of fungi, actinomyces, algae, insects,
protozoa, plants, and bacteria. Those extracts showing inhibitory
activity can then be analyzed to isolate the active molecule. See,
e.g., Nisbet (1997) Curr. Opin. Biotechnol. 8:708-712; Turner (1996) J.
Ethnopharmacol. 51:3943; Borris (1996) J. Ethnopharmacol. 51:29-38; Suh
(1995) Anticancer Res. 15:233-239.
[0293] d. Inhibitory Oligonucleotides
[0294] One particularly useful set of inhibitors provided by the
present invention includes oligonucleotides that are able to either
bind mRNA encoding mTERT protein or to the mTERT gene, in either case
preventing or inhibiting the production of functional mTERT protein.
Other oligonucleotides of the invention interact with mTERT's RNA
moiety, or are able to prevent binding of telomerase enzyme or mTERT to
its DNA/telomere target, or one telomerase component to another, or to
a substrate. Such oligonucleotides can also bind the telomerase enzyme
or mTERT protein and inhibit a partial activity, as described above
(such as its processive activity, its reverse transcriptase activity,
its nucleolytic activity, and the like). The association can be though
sequence specific hybridization to another nucleic acid or by general
binding, as in an aptamer.
[0295] Another useful class of inhibitors includes oligonucleotides
which cause inactivation or cleavage of mTERT mRNA or mTERC. That is,
the oligonucleotide is chemically modified or has enzyme activity which
causes such cleavage, such as is the case with ribozymes. As noted
above, one may screen a pool of many different such oligonucleotides
for those with the desired activity.
[0296] Another useful class of inhibitors includes oligonucleotides
which bind polypeptides. Double- or single-stranded DNA or
single-stranded RNA molecules that bind to specific polypeptide targets
are called "aptamers." The specific oligonucleotide-polypeptide
association may be mediated by electrostatic interactions. For example,
aptamers specifically bind to anion-binding exosites on thrombin, which
physiologically binds to the polyanionic heparin (Bock (1992) Nature
355:564-566). Because mTERT protein binds both mTERC (or hTERC) and its
DNA substrate, and because the present invention provides mTERT and
other mTERT-associated proteins in isolated and purified forms in large
quantities, those of skill in the art can readily screen for
mTERT-binding aptamers using the methods of the invention.
[0297] Antagonists of telomerase-mediated DNA replication can also be
based on inhibition of mTERC (Norton (1996) Nature Biotechnology
14:615-619) through complementary sequence recognition or cleavage, as
through ribozymes.
[0298] Telomerase activity can be inhibited by targeting mTERT mRNA
with antisense oligonucleotides capable of binding mTERT mRNA. In some
situations, naturally occurring nucleic acids used as antisense
oligonucleotides may need to be relatively long (18 to 40 nucleotides)
and present at high concentrations, a wide variety of synthetic,
non-naturally occurring nucleotide and nucleic acid analogues are known
which can address this potential problem. For example, peptide nucleic
acids (PNAs) containing non-ionic backbones, such as N-(2-aminoethyl)
glycine units can be used. PNAs targeting hTERC have been described, as
well as methods for internalizing such PNAs in cells. See, U.S. Ser.
No. 08/630,019, filed Apr. 9, 1996, and U.S. Ser. No. 08/838,545 and
PCT/US/97/05931, filed on Apr. 9, 1997 (also, see Norton (1996) supra).
Antisense oligonucleotides having phosphorothioate linkages can also be
used, as described in WO 97/03211; WO 96/39154; Mata (1997) Toxicol
Appl Pharmacol 144:189-197; Antisense Therapeutics, ed. Sudhir Agrawal
(Humana Press, Totowa, N.J., 1996). Antisense oligonucleotides having
synthetic DNA backbone analogues provided by the invention can also
include phosphorodithioate, methylphosphonate, phosphoramidate, alkyl
phosphotriester, sulfamate, 3'-thioacetal, methylene(methylimino),
3'-N-carbamate, and morpholino carbamate nucleic acids, and other
synthetic, non-naturally occurring nucleotide and oligonucleotide
mimetics.
[0299] As noted above, combinatorial chemistry methodology can be used
to create vast numbers of oligonucleotides that can be rapidly screened
for specific oligonucleotides that have appropriate binding affinities
and specificities toward any target, such as the mTERT proteins of the
invention, can be utilized (see Gold (1995) J. of Biol. Chem.
270:13581-13584).
[0300] i. Inhibitory Ribozymes
[0301] Ribozymes act by binding to a target RNA through the target RNA
binding portion of a ribozyme which is held in close proximity to an
enzymatic portion of the ribozyme that cleaves the target RNA. Thus,
the ribozyme recognizes and binds a target RNA through complementary
base-pairing, and once bound to the correct site, acts enzymatically to
cleave and inactivate the target RNA. Cleavage of a target RNA in such
a manner will destroy its ability to direct synthesis of an encoded
protein if the cleavage occurs in the coding sequence. After a ribozyme
has bound and cleaved its RNA target, it is typically released from
that RNA and so can bind and cleave new targets repeatedly.
[0302] In some circumstances, due to the enzymatic nature of a
ribozyme, ribozyme technology can be advantageous over other
technologies, such as antisense technology (where a nucleic acid
molecule simply binds to a nucleic acid target to block its
transcription, translation or association with another molecule) as the
effective concentration of ribozyme necessary to effect a therapeutic
treatment can be lower than that of an antisense oligonucleotide. This
potential advantage reflects the ability of the ribozyme to act
enzymatically. Thus, a single ribozyme molecule is able to cleave many
molecules of target RNA. In addition, a ribozyme is typically a highly
specific inhibitor, with the specificity of inhibition depending not
only on the base pairing mechanism of binding, but also on the
mechanism by which the molecule inhibits the expression of the RNA to
which it binds. That is, the inhibition is caused by cleavage of the
RNA target, and so specificity is defined as the ratio of the rate of
cleavage of the targeted RNA over the rate of cleavage of non-targeted
RNA. This cleavage mechanism is dependent upon factors additional to
those involved in base pairing. Thus, the specificity of action of a
ribozyme can be greater than that of an antisense oligonucleotide
binding the same RNA site.
[0303] The enzymatic ribozyme RNA molecule has complementarity to the
target, such as the mRNA encoding mTERT. The enzymatic ribozyme RNA
molecule is able to cleave RNA and thereby inactivate a target RNA
molecule. The complementarity functions to allow sufficient
hybridization of the enzymatic ribozyme RNA molecule to the target RNA
for cleavage to occur. One hundred percent complementarity is
preferred, but complementarity as low as 50-75% may also be employed.
The present invention provides ribozymes targeting any portion of the
coding region for an mTERT gene or gene product, i.e., any ribozyme
that can cleave a TERT mRNA or a TERT gene in a manner that will
inhibit the translation or transcription of the mRNA and thus reduce
telomerase activity. In addition, the invention provides ribozymes
targeting the nascent, unspliced RNA transcript of the mTERT gene to
reduce telomerase activity.
[0304] The enzymatic ribozyme RNA molecule can be formed in a
hammerhead motif, but may also be formed in the motif of a hairpin,
hepatitis delta virus, group I intron or RNaseP-like RNA (in
association with an RNA guide sequence). Examples of such hammerhead
motifs are described by Rossi (1992) Aids Research and Human
Retroviruses 8:183; hairpin motifs by Hampel (1989) Biochemistry
28:4929, and Hampel (1990) Nuc. Acids Res. 18:299; the hepatitis delta
virus motif by Perrotta (1992) Biochemistry 31:16; the RNaseP motif by
Guerrier-Takada (1983) Cell 35:849; and the group I intron by Cech, et
al., U.S. Pat. No. 4,987,071. The recitation of these specific motifs
is not intended to be limiting; those skilled in the art will recognize
that an enzymatic RNA molecule of this invention has a specific
substrate binding site complementary to one or more of the target gene
RNA regions, and has nucleotide sequence within or surrounding that
substrate binding site which imparts an RNA cleaving activity to the
molecule.
[0305] ii. Delivery of mTERT
Inhibitory Oligonucleotides
[0306] The mTERT-inhibitory oligonucleotides of the invention can be
transferred into the cell using a variety of techniques well known in
the art. For example, oligonucleotides can be delivered into the
cytoplasm spontaneously, without specific modification. Alternatively,
they can be delivered by the use of liposomes which fuse with the
cellular membrane or are endocytosed, i.e., by employing ligands
attached to the liposome, or attached directly to the oligonucleotide,
that bind to surface membrane protein receptors of the cell resulting
in endocytosis. For example, a DNA binding protein, e.g., HBGF-1, is
known to transport oligonucleotides into a cell. See, e.g., Tseng
(1997) J. Biol. Chem. 272:25641-25647; Satoh (1997) Biochem. Biophys.
Res. Commun. 238:795-799, describing efficient gene transduction by
Epstein-Barr-virus-based vectors coupled with cationic liposome and
HVJ-liposome.
[0307] The procedures for delivering the oligonucleotides of the
invention to cells in vitro are useful in vivo. For example, by using
liposomes, particularly where the liposome surface carries ligands
specific for target cells, or arc otherwise preferentially directed to
a specific organ, one may provide for the introduction of the
oligonucleotides into the target cells in vivo. See, e.g.,
Huwyler(1997) J. Pharmacol. Exp. Ther. 282:1541-1546, describing
receptor mediated delivery using immunoliposomes.
[0308] Alternatively, the cells may be permeabilized to enhance
transport of the oligonucleotides into the cell, without injuring the
host cells. See, e.g., Verspohl (1997) Cell. Biochem. Funct.
15:127-134; Kang (1997) Pharm. Res. 14:706-712; Bashford (1994) Methods
Mol. Biol. 27:295-305, describing use of bacterial toxins for membrane
permeabilization; and for general principles of membrane
permeabilization, see Hapala (1997) Crit. Rev. Biotechnol. 17:105-122.
[0309] e. Telomerase-associated
Proteins as Dominant Negative Mutants
[0310] In one embodiment of the invention, telomerase-associated
proteins are used as modulators of murine telomerase enzyme and mTERT
activity. Telomerase-associated proteins include chromosomal
structures, such as histones, nuclear matrix protein, cell
division/cell cycle control proteins and the like. Other
telomerase-associated proteins which can be used as modulators for the
purpose of the invention include p80, p95, and human proteins, such as
TP1 (Saito (1997) Genomics 46:46-50), TPC-2, TPC-3 (U.S. Ser. No.
08/710,249, filed Sep. 13, 1996) and PIN2 (Shen (1997) Proc. Natl.
Acad. Sci. USA 94:13618-13623), TRF-1 and TRF-2 (Chong (1995) Science
270:1663-1667; Broccoli (1997) "Human telomeres contain two distinct
Myb-related proteins, TRF1 and TRF2," Nat. Genet. 17:231-235). In
addition, TERT binding fragments of these chromosomal
telomerase-associated proteins can be identified by the skilled artisan
in accordance with the methods of the invention and used as modulators
of telomerase activity (see also, e.g., Lauber (1997) J. Biol. Chem.
272:24657-24665, to identify nuclear matrix DNA attachment sites).
[0311] i. Identifying
Telomerase-associated Proteins for Use as Modulators
[0312] In one embodiment of the invention, mTERT and mTERT-containing
telomerase enzyme are used to identify telomerase-associated proteins,
i.e., telomerase accessory proteins which modulate or otherwise
complement telomerase activity. As noted above, these proteins or
fragments thereof can modulate function by causing the dissociation or
prevention the association of the telomerase enzyme complex, prevent
the assembly of the telomerase complex, prevent mTERT from binding to
its nucleic acid complement or to its DNA template, prevent mTERT from
binding nucleotides, or prevent, augment, or inhibit any one, several
or all of the partial activities of telomerase enzyme or mTERT protein.
[0313] The skilled artisan can use a variety of well-known techniques
to identify telomerase-associated proteins, including phage display
(Katz (1997) Annu. Rev. Biophys. Biomol. Struct. 26:27-45), the two
hybrid system (as in James (1996) Genetics 144:1425-1436; Adey (1997)
Biochem. J. 324:523-528; Cowell (1997) "Yeast two-hybrid library
screening," Methods Mol. Biol. 69:185-202), and disease correlation.
Other well-known techniques include co-immunoprecipitation analysis, as
used in Zhao (1994) J. Biol. Chem. 269:15577-15582. Another well known
technique for isolating co-associating proteins involves the use of
chemical cross-linkers, including cleavable cross-linkers dithiobis
(succinimidylpropionate) and
3,3'-dithiobis(sulfosuccinimidyl-propionate); see e.g., Tang (1996)
Biochemistry 35:8216-8225. Photocross linking experiments implicated a
123 kd protein in the specific binding of telomeric DNA substrate in
Euplotes aediculatus (Lingner (1996) Proc. Natl. Aca. Sci. U.S.A.
93:10712).
[0314] ii. Dominant-negative Mutants
of mTERT
[0315] The present invention provides non-functional,
"dominant-negative" mTERT mutants. Dominant-negative mutant forms of
enzymes can be used to competitively substitute for endogenous forms of
the enzyme to affect the function, structure (e.g., as as
herterocomplex, a quaternary structure) location, half-life, or
compartmentalization of the enzyme. The invention provides for mTERT
telomerase mutant forms that can competitively interfere with or
replace wild-type (native) form of mTERT. Such mutant mTERTs can, e.g.,
interfere with or replace native mTERT in the formation of the
telomerase enzyme complex (i.e., mTERT with mTERC) or compete for
mTERT-telomere binding sites. In this manner, the effective amounts of
functional telomerase in the cell can be reduced or altered or a new
function or form of telomerase can be created. This can be used, e.g.,
to have a therapeutic effect, by reducing the level of telomerase
activity in a cancer cell, to modulate telomere length in a cell, study
the consequence of a TERT mutation, or to elucidate biological
functions of a TERT or its mutants.
[0316] Mutations creating dominant-negative forms of mTERT can be
generated by, e.g., mutating any of the above-described TERT motifs or
other codons of the mTERT gene. For example, codons for the conserved
amino acid residues in each of any of the conserved TERT motifs can be
changed to other codons, resulting in a variety of coding sequences
which express a partially non-functional mTERT. Eight highly conserved
motifs have been identified in TERTs of different species, including
mouse and man, see Lingner (1997) supra. FIG. 3 shows the alignment of
mTERT with hTERT, and positions of motifs are indicated. FIGS. 4 and 5
show mTERT motifs in relation to the sequence conservation between
mTERT and other TERTs: human, Euplotes aediculatus, Saccharomyces
cerevisiae, Schizosaccharomyces
pombe. Thus, the present invention provides a wide variety of "mutated"
telomerase enzymes and mTERT proteins which have a partial activity but
not full activity of telomerase enzyme.
[0317] For example, one such telomerase is able to bind telomeric
structures, but not bind telomerase-associated RNA (i.e., mTERC). If
expressed at high enough levels, such a telomerase mutant can deplete a
necessary telomerase component (e.g., the telomere binding site) and
thereby function as an inhibitor of wild-type telomerase activity. A
mutated telomerase acting in this manner is as an antagonist or a
so-called "dominant negative" mutant.
[0318] Example 8 below describes three mutants of mTERT which are
predicted to be deficient in a telomerase activity. These mutations
change amino acids in the conserved RT motifs previously shown to be
essential for RT function (Lingner (1997) supra). The predictions are
based on similar results for analogous mutations in hTERT (Weinrich
(1997) supra). The mutations are created using the procedures described
in Weinrich (1997) supra.
5. Definitions
[0319] To facilitate understanding the invention, a number of terms are
defined below.
[0320] The term "antibody" refers to a polypeptide substantially
encoded by an immunoglobulin gene or immunoglobulin genes, or fragments
or synthetic or recombinant analogues thereof which specifically bind
and recognize analytes and antigens. The recognized immunoglobulin
genes include the kappa, lambda, alpha, gamma, delta, epsilon and mu
constant region genes, as well as myriad immunoglobulin variable region
genes. Light chains are classified as either kappa or lambda. Heavy
chains are classified as gamma, mu, alpha, delta, or epsilon, which in
turn define the immunoglobulin classes, IgG, IgM, IgA, IgD and IgE,
respectively. An exemplary immunoglobulin (antibody) structural unit
comprises a tetramer. Each tetramer is composed of two identical pairs
of polypeptide chains, each pair having one "light" (about 25 kD) and
one "heavy" chain (about 50-70 kD). The N-terminus of each chain
defines a variable region of about 100 to 110 or more amino acids
primarily responsible for antigen recognition. The terms variable light
chain (VL) and variable heavy chain (VH) refer to these light and heavy
chains respectively. Antibodies exist, e.g., as intact immunoglobulins
or as a number of well characterized fragments produced by digestion
with various peptidases, see, FUNDAMENTAL IMMUNOLOGY, 3RD ED., W. E.
Paul, ed., Raven Press, N.Y. (1993). While various antibody fragments
are defined in terms of the digestion of an intact antibody, one of
skill will appreciate that such fragments may be synthesized de novo
either chemically or by utilizing recombinant DNA methodologies, for
example, recombinant single chain Fv or antibodies or fragments thereof
displayed on the surface of a phage, virus or a cell. The term
"immunologically reactive conditions" refers to an environment in which
antibodies can bind to antigens, such as an mTERT of the invention. As
discussed below, this can be an immunological binding assay. The phrase
"specifically binds to an antibody" when referring to a protein or
peptide, refers to a binding reaction which is determinative of the
presence of the protein in the presence of a heterogeneous population
of proteins and other biologics. Thus, under designated immunoassay
conditions, the specified antibodies bind to a particular protein and
do not bind in a significant amount to other proteins present in the
sample. Specific binding to an antibody under such conditions may
require an antibody that is selected for its specificity for a
particular protein. For example, antibodies specific for the mTERT
protein of this invention or to any portion or the protein defined by
the sequence of SEQ ID NO:2 can be selected to immunoreact specifically
with all murine mTERT species of the invention or only a single mTERT
specie (an allele, homologue, or isoform), and not with non-mouse TERT
proteins or non-telomerase proteins. As described below, a variety of
immunoassay formats may be used to select antibodies specifically
immunoreactive with a particular protein, such as mTERT. For example,
solid-phase ELISA immunoassays are routinely used to select monoclonal
antibodies specifically immunoreactive with mTERT. See Harlow and Lane,
supra, for a description of immunoassay formats and conditions that can
be used to determine specific immunoreactivity, a specific or selective
reaction is one which generates a signal at least twice (2*) over
background signal or "noise."
[0321] The term "buffered aqueous solution compatible with telomerase
activity" refers to conditions suitable for in vitro reactions, such as
in vitro transcription and translation reactions, or activity assays,
i.e., compatible physiological conditions. The term refers to
temperature, pH, ionic strength, viscosity, and like biochemical
parameters which can be compatible with a telomerase enzyme or mTERT
activity, full or partial, e.g., such as those conditions that exist in
a viable organism, e.g. conditions which typically exist
intracellularly in a viable cultured eukaryotic cell, such as a yeast
or a mammalian cell. Compatible physiologic conditions for mTERT and
telomerase enzyme activity (conditions suitable for in vitro
reactions), however, can be substantially different from conditions
which typically exist intracellularly. For example, the intracellular
conditions in a yeast cell grown under typical laboratory culture
conditions are considered physiological conditions. In general, in
vitro physiological conditions comprise 50-200 mM NaCl or KCl, pH
6.5-8.5, 20-45 EC and 0.001-10 mM divalent cation (e.g., Mg<++> ,
Ca<++> ), preferably about 150 mM NaCl or KCl, pH 7.2-7.6, 5 mM
divalent cation, and often include 0.01-1.0 percent nonspecific protein
(e.g., BSA). In addition, a non-ionic detergent (Tween, NP40, Triton
X-100) can often be present, usually at about 0.001 to 2%, typically
0.05-0.2% (v/v). Particular aqueous conditions may be selected by the
practitioner according to conventional methods. For general guidance,
the following buffered aqueous conditions can be applicable: 10-250 mM
NaCl, 5-50 mM Tris HCl, pH 5-8, with optional addition of divalent
cation(s) and/or: metal chelators; nonionic detergents; membrane
fractions; antifoam agents; and/or scintillants.
[0322] The term "conservative substitution" refers to a change in the
amino acid composition of a protein, such as the mTERT of the
invention, that does not substantially alter the protein's activity.
This includes conservatively substituted variations of a particular
amino acid sequence, ie., amino acid substitutions of those amino acids
that are not critical for protein activity or substitution of amino
acids with other amino acids having similar properties (e.g., acidic,
basic, positively or negatively charged, polar or non-polar, etc.) such
that the substitutions of even critical amino acids do not
substantially alter activity. Conservative substitution tables
providing functionally similar amino acids are well known in the art.
The following six groups each contain amino acids that are conservative
substitutions for one another: 1) Alanine (a), Serine (S), Threonine
(T); 2) Aspartic acid (D), Glutamic acid (E); 3) Asparagine (N),
Glutaine (Q); 4) Arginine (R), Lysine (K); 5) Isoleucine (1), Leucine
(L), Methionine (M), Valine (V); and 6) Phenylalanine (F), Tyrosine
(Y), Tryptophan (W) (see also, Creighton (1984) Proteins, W.H. Freeman
and Company). One of skill in the art will appreciate that the
above-identified substitutions are not the only possible conservative
substitutions. For example, for some purposes, one may regard all
charged amino acids as conservative substitutions for each other
whether they are positive or negative. In addition, individual
substitutions, deletions or additions which alter, add or delete a
single amino acid or a small percentage of amino acids in an encoded
sequence can also be considered "conservatively substituted
variations." The term "conservative substitution" also refers to a
change in a nucleic acid sequence such that the substitution does not
substantially alter the contemplated activity of the nucleic acid, for
example, as not changing the activity of the protein encoded by the
nucleic acid, a nucleic acid sequence of the invention implicitly
encompasses conservatively modified variants thereof (e.g. degenerate
codon substitutions) and complementary sequences and not just the
sequence explicitly indicated. Specifically, degenerate codon
substitutions may be achieved by generating sequences in which the
third position of one or more selected (or all) codons is substituted
with mixed-base and/or deoxyinosine residues (Batzer (1991) Nucleic
Acid Res. 19:5081; Ohtsuka (1985) J. Biol. Chem. 260:2605-2608;
Rossolini (1994) Mol. Cell. Probes 8:91-98).
[0323] The term "expression vector" refers to any recombinant
expression system for the purpose of expressing a nucleic acid sequence
of the invention, as SEQ ID NO:1, in vitro or in vivo, constitutively
or inducibly, in any cell, including prokaryotic, yeast, fungal, plant,
insect or mammalian cells. The term includes linear or circular
expression vectors. The term includes expression vectors that remain
episomal or integrate into the host cell genome. The expression vectors
can have the ability to self-replicate or not, i.e., drive only
transient expression in a cell. The term includes recombinant
expression vector "cassettes" which contain only the minimum elements
needed for transcription of the recombinant nucleic acid. See, e.g.,
Arnaud (1997) Genex 199:149-156.
[0324] A "fusion protein" refers to a composition comprising at least
one polypeptide or peptide domain which is associated with a second
typically polypeptide or peptide domain. The polypeptide or peptide
domain can comprise an mTERT or subsequence thereof. The second domain
can be a polypeptide, peptide, polysaccharide, polynucleotide, or the
like. The "fusion" can be an association generated by a chemical
linking or by a charge (electrostatic attraction, i.e., salt bridges,
H-bonding, etc.) interaction. If the polypeptides are recombinant, the
"fusion protein" can be translated from a common message.
Alternatively, the compositions of the domains can be linked by any
chemical or electrostatic means. The invention includes compositions
which are "fusion proteins" comprising mTERT and non-mTERT (exogenous)
polypeptide sequences or compositions to aid in cell targeting,
purification, expression and/or detection of mTERT and murine
telomerase enzyme.
[0325] The terms "isoform," "allele," and "homologue" refer to a
nucleic acid or polypeptide mTERT specie. The nucleic acid or protein
can be considered an mTERT isoform, homologue or allele if it shares at
least 40 percent to 50 percent sequence identity to any known mTERT
specie, including but not limited to the mTERT identified by SEQ ID
NO:1 or SEQ ID NO:2, respectively.
[0326] As used herein, "isolated," when referring to a molecule or
composition, such as, e.g., an mTERT or a telomerase-associated nucleic
acid or polypeptide, means that the molecule or composition is
separated from at least one other compound, such as a protein, other
nucleic acids (e.g., RNAs), or other contaminants with which it is
associated in vivo or in its naturally occurring state. Thus, an mTERT
is considered isolated when the mTERT has been isolated from any other
component with which it is naturally associated, e.g., cell membrane,
as in a cell extract. An isolated composition can, however, also be
substantially pure. An isolated composition can be in a homogeneous
state and can be in a dry or an aqueous solution. Purity and
homogeneity can be determined, for example, using analytical chemistry
techniques such as polyacrylamide gel electrophoresis (SDS-PAGE) or
high performance liquid chromatography (HPLC).
[0327] The term "label" refers to a detectable composition, such as by
spectroscopic, photochemical, biochemical, immunochemical, physical or
chemical means. For example, useful labels include <32> P,
<35> S, <3> H, <14> C, <125> I, <131> I,
fluorescent dyes (e.g., FITC, rhodamine, lanthanide phosphors),
electron-dense reagents, enzymes, e.g. as commonly used in an ELISA
(e.g., horseradish peroxidase, beta-galactosidase, luciferase, alkaline
phosphatase), biotin, dioxigenin, or haptens and proteins for which
antisera or monoclonal antibodies are available. The label can be
directly incorporated into the nucleic acid, peptide or other target
compound to be detected, or it can be attached to a probe or antibody
which hybridizes or binds to the target, a peptide can be made
detectable by incorporating predetermined polypeptide epitopes
recognized by a secondary reporter (e.g., leucine zipper pair
sequences, binding sites for secondary antibodies, transcriptional
activator polypeptide, metal binding domains, epitope tags). In some
embodiments, labels are attached by spacer arms of various lengths to
reduce potential steric hindrance or impact on other useful or desired
properties. See e.g., Mansfield (1995) Mol. Cell Probes 9:145-156.
[0328] The term "modulator" refers to any synthetic or natural compound
or composition that can change in any way either the "full" or any
"partial activity" of a TERT or a telomerase enzyme, a modulator can be
an agonist or an antagonist, a modulator can be, but is not limited to,
any organic and inorganic compound; including, e.g., small molecules,
peptides, proteins, sugars, nucleic acids, fatty acids and the like.
[0329] The term "murine" refers to any and all members of the family
Muridae, including rats and mice. As used herein, the term "mouse" and
"mice" encompass all members of the family Muridae. Thus, the term
"mTERT," as defined below, "murine TERT" and "mouse TERT" are
equivalent and encompass TERT species from all members of the family
Muridae.
[0330] The term "nucleic acid molecule" or "nucleic acid sequence"
refers to a deoxyribonucleotide or ribonucleotide oligonucleotide in
either single- or double-stranded form. The term encompasses nucleic
acids, i.e., oligonucleotides, containing known analogues of natural
nucleotides which have similar or improved binding or other properties,
for the purposes desired, as the reference nucleic acid. The term also
includes nucleic acids which are metabolized in a manner similar to
naturally occurring nucleotides or at rates that are improved thereover
for the purposes desired. The term also encompasses nucleic-acid-like
structures with synthetic backbones. DNA backbone analogues provided by
the invention include phosphodiester, phosphorothioate,
phosphorodithioate, methyl-phosphonate, phosphoramidate, alkyl
phosphotriester, sulfamate, 3'-thioacetal, methylene (methylimino),
3'-N-carbamate, morpholino carbamate, and peptide nucleic acids (PNAs);
see Oligonucleotides and Analogues, a Practical Approach, edited by F.
Eckstein, IRL Press at Oxford University Press (1991); Antisense
Strategies, Annals of the New York Academy of Sciences, Volume 600,
Eds. Baserga and Denhardt (NYAS 1992); Milligan (1993) J. Med. Chem.
36:1923-1937; Antisense Research and Applications (1993, CRC Press) in
its entirety and specifically Chapter 15, by Sanghvi, entitled
"Heterocyclic base modifications in nucleic acids and their
applications in antisense oligonucleotides." PNAs contain non-ionic
backbones, such as N-(2-aminoethyl) glycine units, as described in U.S.
Ser. No. 08/630,019, filed 9 Apr. 1996, and the US CIP U.S. Ser. No.
08/838,545 and PCT application PCT/US/97/0593 1, both filed on Apr. 9,
1997. Phosphorothioate linkages are described in WO 97/03211; WO
96/39154; Mata (1997) Toxicol Appl Pharmacol 144:189-197. Other
synthetic backbones encompassed by the term include, e.g.,
methylphosphonate linkages or alternating methylphosphonate and
phosphodiester linkages (Strauss-Soukup (1997) Biochemistry
36:8692-8698), and benzylphosphonate linkages, which, when compared
with unmodified oligonucleotides and methylphosphonates, are more
stable against nucleases and exhibit a higher lipophilicity (Samstag
(1996) Antisense Nucleic Acid Drug Dev 6:153-156). The term nucleic
acid is used interchangeably with gene, cDNA, mRNA, oligonucleotide
primer, probe and amplification product. The terms "exogenous nucleic
acid" and "heterologous nucleic acid" refer to a nucleic acid that has
been isolated, synthesized, cloned, ligated, excised in conjunction
with another nucleic acid, in a manner that is not found in nature,
and/or introduced into and/or expressed in a cell or cellular
environment other than or at levels or forms different than the cell or
cellular environment in which said nucleic acid or protein is found in
nature. The term encompasses both nucleic acids originally obtained
from a different organism or cell type than the cell type in which it
is expressed and also nucleic acids that are obtained from the same
cell line as the cell line in which it is expressed.
[0331] The term "recombinant," when used with reference to a cell, or
to a nucleic acid, protein or vector, refers to a material or a
material corresponding to the natural or native form of the material,
that has been modified by the introduction of a new moiety or
alteration of an existing moiety, or is identical thereto but produced
or derived from synthetic materials. For example, recombinant cells
express genes that are not found within the native (non-recombinant)
form of the cell or express native genes or gene products that are
otherwise expressed at a different level, typically, under-expressed or
not expressed at all. The term "recombinant means" encompasses all
means of expressing, ie., transcription or translation of an isolated
and/or cloned nucleic acid in vitro or in vivo. For example, the term
"recombinant means" encompasses techniques where a recombinant nucleic
acid, such as a cDNA encoding a protein, is inserted into an expression
vector (including "expression cassettes"), the vector is introduced
into a cell, i.e., the cell is "transfected" or "transformed" and the
cell expresses the protein. "Recombinant means" also encompass the
ligation of nucleic acids having coding or transcriptional regulatory
(e.g., promoter) sequences from different sources into one expression
cassette or vector for expression of a fusion protein, constitutive
expression of a protein, or inducible expression of a protein, such as
the mTERT protein of the invention.
[0332] The terms "homology," "sequence identity" and "sequence
similarity" refers to a degree of complementarity or sequence identity.
There may be partial homology or complete homology (ie., identity), a
partially complementary sequence is one that at least partially
inhibits a completely complementary sequence from hybridizing to a
target nucleic acid and can be referred to using the functional term as
"substantially homologous" to the completely complementary sequence.
The inhibition of hybridization of the completely complementary
sequence to the target sequence may be examined using a hybridization
assay (Southern or Northern blot, solution hybridization and the like)
under conditions of low stringency, a substantially homologous sequence
or probe will compete for and inhibit the binding (i.e., the
hybridization) of a completely homologous nucleic acid to a target
nucleic acid under conditions of low stringency. This is not to say
that conditions of low stringency are such that non-specific binding is
permitted; low stringency conditions require that the binding of two
sequences to one another be a specific (ie., selective) interaction.
The absence of non-specific binding may be tested by the use of a
second target which lacks even a partial degree of complementarity; in
the complete absence of non-specific binding the probe will not
hybridize to the second non-complementary target. The terms "sequence
identity," "sequence similarity" and "homology" refer to two or more
sequences, such as the diverse nucleic acid and amino acid sequences of
the mTERT proteins of the telomerase of the invention, that, when
optimally aligned, as with the programs BLAST, GAP, FASTA or BESTFIT,
share at least 40 percent to 50 percent sequence identity, and
preferably at least 60 percent or greater sequence identity.
"Percentage amino acid sequence identity" refers to a comparison of the
sequences of two TERT nucleic acids or polypeptides which, when
optimally aligned, have approximately the designated percentage of the
same nucleotides or amino acids, respectively. For example, "60%
sequence identity" and "60% homology" refer to a comparison of the
sequences of two nucleic acids or polypeptides which, when optimally
aligned, have 60% identity.
[0333] The term "an mTERT" polypeptide comprising an amino acid
sequence with significant sequence identity to a motif refers to mTERT
proteins which are considered to have a statistically significant
sequence identity, ie., have significant homology or be significantly
identical, at the amino acid sequence level in a conserved region of a
TERT protein, such as the motif sequences defined herein. Two TERT
proteins are considered to have a statistically significant sequence
identity in the conserved region if, after adjusting for deletions,
additions and the like, the conserved regions have at least out 20% to
30% sequence identity or greater sequence identity, preferably higher,
for example, about 40% to 50% or higher (ie., 80% to 90%) if the region
of comparison is shorter, ie., a region of about ten consecutive amino
acids.
[0334] The terms "stringent hybridization," "stringent conditions," or
"specific hybridization conditions" refer to conditions under which an
oligonucleotide (when used, for example, as a probe or primer) will
hybridize to its target subsequence, such as an mTERT sequence of a
nucleic acid in an expression vector of the invention but not to a
non-telomerase sequence. Stringent conditions are sequence-dependent.
Thus, in one set of stringent conditions an oligonucleotide probe will
hybridize to only one specie mTERT of the invention. In another set of
stringent conditions (less stringent) an oligonucleotide probe will
hybridize to all species of mTERT but not to non-telomerase nucleic
acids. Longer sequences hybridize specifically at higher temperatures.
Stringent conditions are selected to be about 5[deg.] C. lower than the
thermal melting point (Tm) for the specific sequence at a defined ionic
strength and pH. The Tm is the temperature (under defined ionic
strength, pH, and nucleic acid concentration) at which 50% of the
probes complementary to the target sequence hybridize to the target
sequence at equilibrium (if the target sequences are present in excess,
at Tm, 50% of the probes are occupied at equilibrium). Typically,
stringent conditions will be those in which the salt concentration is
less than about 1.0 M sodium ion, ie., about 0.01 to 1.0 M sodium ion
concentration (or other salts) at pH 7.0 to 8.3 and the temperature is
at least about 30[deg.] C. for short probes (e.g., 10 to 50
nucleotides) and at least about 60[deg.] C. for long probes (e.g.,
greater than 50 nucleotides). Stringent conditions may also be achieved
with the addition of destabilizing agents such as formamide. Often,
high stringency wash conditions are preceded by low stringency wash
conditions to remove background probe signal. An example of medium
stringency wash conditions for a duplex of, e.g., more than 100
nucleotides, is 1*SSC at 45[deg.] C. for 15 minutes (see Sambrook for a
description of SSC buffer). An example of a low stringency wash for a
duplex of, e.g., more than 100 nucleotides, is 4-6*SSC at 40[deg.] C.
for 15 minutes, a signal to noise ratio of 2* (or higher) than that
observed for an unrelated probe in the particular hybridization assay
indicates detection of a "specific hybridization." Nucleic acids which
do not hybridize to each other under stringent conditions can still be
substantially identical if the polypeptides which they encode are
substantially identical. This can occur, e.g., when a nucleic acid is
created that encodes for conservative substitutions. Stringent
hybridization and stringent hybridization wash conditions are different
under different environmental parameters, such as for Southern and
Northern hybridizations. An extensive guide to the hybridization of
nucleic acids is found in Tijssen (1993) supra.
[0335] The term "subsequence" refers to a sequence of a nucleic acid or
protein or an amino acid that comprises a part of a longer sequence of
a nucleic acid or a protein (e.g., polypeptide), respectively.
[0336] The term "test compound" refers to any synthetic or natural
compound or composition. The term includes all organic and inorganic
compounds; including, for example, small molecules, peptides, proteins,
sugars, nucleic acids, fatty acids and the like.
[0337] The terms "transformed cell" and "transfected cell" refers to
any cell into which a heterologous or exogenous nucleic acid has been
inserted, either transiently or stably, by recombinant means, i.e., by
human intervention.
[0338] The terms "TERT" and "telomerase reverse transcriptase" refer to
a telomere-specific RNA-dependent DNA polymerase protein, the
telomerase holoenzyme without an RNA component, the catalytic subunit
of the telomerase enzyme complex. The term "telomerase," "telomerase
enzyme" and "telomerase enzyme complex" refers to a TERT with at least
one RNA component, i.e., an RNA moiety used as a template for DNA
synthesis. The telomerase enzyme can also include other
telomerase-associated compositions. The telomerase can utilize a
portion of its RNA moiety as a template to specify the addition of
telomeric DNA repeat sequences to chromosomal ends. The term "mTERT"
and "murine TERT" refer to murine TERT nucleic acids and proteins with
common structural and functional characteristics. mTERT nucleic acids
can be characterized as an mTERT protein having a calculated molecular
weight of between about 50 and 150 kDa and specifically binding to an
antibody raised against a protein having a sequence of amino acids as
in SEQ ID NO:2 or a subsequence thereof or having at least 60% amino
acid sequence identity to a protein having a sequence of amino acids as
in SEQ ID NO:2. mTERT nucleic acids also comprise nucleic acids which
specifically hybridize to SEQ ID NO:1 under stringent conditions, and
nucleic acids encoding a protein which specifically binds to an
antibody directed against an mTERT protein having a sequence of amino
acids as in SEQ ID NO:2. mTERT proteins can be characterized as having
a calculated molecular weight of about 50 to 150 kDa and specifically
binding to an antibody raised against a mTERT protein having a sequence
of amino acids as in SEQ ID NO:2 or subsequence thereof or having 60%
amino acid sequence identity to a mTERT protein having a sequence of
amino acids as in SEQ ID NO:2. Isolated or recombinant mTERT proteins
within the scope of the claimed invention encompass murine proteins
comprising species with common structural characteristics, i.e.,
motifs, as discussed in detail herein. The mTERTs of the invention
include: species capable of catalyzing the synthesis of telomeres when
associated with an RNA moiety, such as mTERC or hTERC; species capable
of one or several or all partial activities of mTERT and telomerase
enzyme; and species such as mTERT isoforms, homologues, and alleles
which are considered mTERT species of the invention because they
contain requisite common structural mTERT characteristics (i.e., TERT
motifs) or sufficient sequence identity with any other mTERT specie.
mTERT species include mTERT from all murine or Muridae family species,
including mice and rats, as defined above. The term "an endogenous
mTERT gene which has been mutated by recombinant means" refers to a
gene which has been altered by a change in coding or non-coding,
transcribed or untranscribed, or mTERT transcriptional regulatory
sequences. If such a mutated gene is in a cell that is placed in an
animal, the resultant transgenic non-human animal can be referred to as
an "mTERT knockout" cell or animal, as described, supra.
[0339] The terms "telomerase activity" and "telomerase reverse
transcriptase activity" ("TERT activity") can refer to either "full" or
any "partial activity" of a TERT or telomerase enzyme. TERT activity
includes the ability to synthesize DNA, such as a telomere or telomeric
DNA, using a nucleic acid template, such as the telomerase RNA, a TERT
"partial activity" can include, but is not limited to, such functions
as the ability of TERT to: bind substrate DNA; bind a telomerase RNA
moiety, i.e., mTERC or hTERC; catalyze the addition of nucleotides to a
DNA substrate; bind deoxynucleotide substrate; exhibit "nucleolytic
activity" (see Collins (1993) Genes Dev 7:1364-1376); bind
telomere-associated proteins or chromosomal structures; exhibit the
"processive" or "non-processive" activity of telomerase (see Morin
(1989) supra); exhibit "reverse-transcriptase-like activity" of
telomerase (see Lingner (1997) supra); bind nucleotides as part of its
processive enzymatic DNA polymerization activity; bind chromosomes in
vivo; bind oligonucleotide primers in vitro (Harrington (1995) J Biol
Chem 270: 8893-8901) or in reconstituted systems; and bind histones,
nuclear matrix protein, cell division/cell cycle control proteins and
the like.
[0340] The examples and embodiments described herein are for
illustrative purposes only, and various modifications or changes in
light thereof will be suggested to persons skilled in the art and
thereby are to be included within the spirit and purview of this
disclosure and scope of the appended claims.
EXAMPLES
[0341] The following examples are offered to illustrate, but not limit
the claimed invention.
Example 1
Isolating, Cloning and Sequencing
mTERT cDNA and Genomic DNA
[0342] The following example details the isolation, cloning and
sequencing of mTERT cDNA and mTERT genomic DNA, including
transcriptional control elements and intronic sequences.
[0343] Mouse cDNA and genomic clones of TERT are provided by the
invention to, e.g., construct homozygous or heterozygous deletions or
other modifications of mTERT (i.e., deletions in either one or both
alleles), e.g., as in mTERT "knockout" cells or mice; construct
recombinant nucleic acids encoding mTERT proteins differing in amino
acid sequence at one or more positions relative to native mTERT;
characterize mTERT biochemistry and biology; identify and isolate
additional mTERT species (alleles, isoforms, homologues); express mTERT
and mTERC or mTERT and hTERC in "knockout" animals, e.g., those unable
to express endogenous TERT or telomerase enzyme; express mTERT and
mTERC or hTERC in cell-free transcription/translation systems; and
express mTERT in cells or organisms which have retained the ability to
express endogenous telomerase and/or mTERC.
[0344] General Techniques for Cloning
of mTERT cDNA and Genomic Sequences
[0345] To obtain a clone of an mTERT, a hybridization step is typically
performed, a probe is constructed from a known mTERT provided by the
invention, such as the nucleic acid sequence set forth in SEQ ID NO:1,
or a TERT from another organism, such as hTERT. The probe can be
synthetically generated or it can be generated by PCR. The probe can
incorporate a synthetic fragment, a PCR fragment or a restriction
fragment(s) of a nucleic acid comprising all or pat of the TERT gene or
the TERT coding sequence, which is then hybridized to DNA or RNA from
the target mouse cell.
[0346] The mouse DNA can be genomic DNA, a genomic DNA library, RNA,
cDNA, a cDNA library, or other sources of nucleic acid. In one
embodiment, a mouse cDNA library is screened to obtain a fragment of
mTERT cDNA. This fragment or its sequence can be further used to
identify a genomic clone or additional cDNA clones. Use of cDNA may
have advantages in that it is typically free of introns. The source of
the cDNA library is important; it is preferably from a tissue known to
possess telomerase activity or TERT RNA. An embryonic stem cell cDNA
library is a preferred source of mTERT mRNA, as telomerase enzyme is
expressed in stem cells.
[0347] The invention provides TERT sequence-containing probes useful
for such screening, including the full length mTERT cDNA (SEQ ID NO:1)
and various fragments of mTERT cDNA. One such probe includes a portion
of TERT encompassing approximately the first third of a TERT cDNA, such
as the first third of mTERT (SEQ ID NO:1). This region is more GC rich
than the rest of the protein and may be preferred for detecting
additional mTERT species in some circumstances. Thus, one embodiment
uses this subfragment of mTERT, or, analogously, the first third of
hTERT, or any other known TERT, as probes in screening for additional
species.
[0348] Another embodiment provides for a probe including a portion of
TERT encompassing approximately the middle third of a TERT cDNA, such
as mTERT cDNA (SEQ ID NO:1). This region encodes a subset of the RT
motifs and is likely to be the most conserved region and so is
preferred in some circumstances. Thus, a preferred embodiment uses this
subfragment of mTERT, or, analogously, the middle third of hTERT, or
any other known TERT, as probes in screening for additional species.
[0349] An additional embodiment provides for a probe that is a portion
of TERT encompassing approximately the last third of a TERT cDNA, such
as the mTERT cDNA (SEQ ID NO:1). An alternative embodiment uses this
subfragment of TERT, or, analogously, the last third of hTERT, or any
other known TERT, as probes in screening.
[0350] The screen can be performed with a mixture of the probes to
ensure the detection of at least one clone. Once a clone is identified,
it can be screened with each probe independently to identify the region
it encompasses. Then, the probes can be used independently to find
missing regions, if any. When an mTERT is identified, a screen of a
mouse genomic library can be performed using the mTERT clone as a
probe. If the initial hybridization uses a non-mouse probe, such as
hTERT, it can be performed at reduced stringency. As isoforms,
homologues, and alleles of mTERT genes are expected to be about 60-95%
identical to other TERTs, such as hTERT, appropriate hybridization
conditions can be readily calculated, see e.g., Sambrook.
[0351] The mouse genomic clone and genomic sequences can be used, e.g,
to prepare constructs for making transgenic mice expressing TERT. The
mTERT constructs of the invention can be used to create an mTERT
knockout cell or mouse by homologous recombination, as discussed herein
in relation to knockout procedures. To clone an entire genomic mTERT,
multiple large genomic lambda clones can be used to span the entire
mouse genomic sequence.
[0352] In one embodiment, a mouse ES library is used to identify a
mouse TERT-encoding nucleic acid clone, a preferred library is the
Mouse Embryonic Stem Cell 5'-STRETCH cDNA library, cat # ML1049a,
Clontech, Palo Alto, Calif., average insert size 1.6 Kb (0.8-4.5 Kb
range), vector=1gt10, oligo dT and random hexamer primed with EcoRI
linkers, RNA source=D3 cell line (pluripotent ES cells) (Doetschman
(1985) J. Embryol. Exp. Morphol. 87:27-45).
[0353] Cloning of the m TERT cDNA and
mTERT Genomic Nucleic Acid
[0354] A conventionally constructed mouse embryonal stem cell cDNA
lambda gt10 phage library (Clontech, Palo Alto, Calif.) was screened
using three human hTERT nucleic acid probes. The probes were designated
A, B, and C, each approximately the same size, encompassing almost the
entire hTERT coding region, running 5' to 3', respectively. These
probes were derived from the hTERT-containing plasmid pGRN121, ATCC
Accession No. ATCC209016, deposited May 6, 1997, and described in U.S.
Ser. No. 08/915,503, U.S. Ser. No. 08/912,951, and, U.S. Ser. No.
08/911,312, all filed Aug. 14, 1997; and in U.S. Ser. No. 08/974,549,
and U.S. Ser. No. 08/974,584, both filed on Nov. 19, 1997. Probe A is
an Eco47111/Eco47111, 1203 base pair long fragment encompassing
residues 729 to 1932 of pGRN121; probe B is a Sph1/Xmn1, 1143 base pair
long fragment encompassing residues 2278 to 3421 of pGRN121; and probe
C is an Xmn1/Msc1, 760 base pair long fragment encompassing residues
3421 to 4181 of pGRN121. The probes were hybridized using a
conventional, low stringency hybridization protocol, with
prehybridization and hybridization solutions containing 35% formamide
at 37[deg.] C. for 12 hours.
[0355] A recombinant phage cDNA clone which specifically hybridized to
the hTERT probe was isolated. A TERT-encoding 2 kb long nucleic acid
insert was isolated, subcloned into a plasmid, and sequenced. The
plasmid with this insert is designated pGRN227. Analysis of this
sequence, including its comparison to known TERT sequences, was
performed. The analysis determined that the insert possessed extensive
sequence homology with hTERT, matching about 70% of the DNA sequence of
hTERT around positions 1870 to 2150 of plasmid pGRN121. The 2 kb insert
was 2006 base pairs long. Sequence analysis indicated that it included
1977 base pairs of mTERT coding sequence, which is about half the mTERT
protein's open reading frame. The insert included some 5' non-coding
sequence and sufficient coding (open reading frame, or ORF) sequence to
identify the TERT motifs 1 and 2, which, based on related TERT
sequences, was determined to be about half of the ORF for the mTERT
protein.
[0356] To isolate the remaining coding sequence, a PCR amplification
reaction was carried out using cDNA prepared from mouse testis polyA+
mRNA (Clontech, Palo Alto, Calif.). PCR amplification primers were
designed: the primer pair included a 5' primer with sequence from the
above-described 2 kb insert (called mTRT.9)
(5'-CTTTTACATCACAGAGAGCAC-3') (SEQ ID NO:15) and a 3' primer from a
conserved region of hTERT (called hTRT.28)
(5'-CTCGGACCAGGGTCCTGAGGAA-3') (SEQ ID NO:8), a conventional RT-PCR
protocol was used. The resultant amplified segment was subcloned into a
plasmid and sequenced. The plasmid with this insert is called mTRT Ra3'
(pGRN230). Analysis of the sequence showed that this cDNA insert
included further coding sequence of mTERT, including new coding
sequence 3' to the initially characterized 2 kb segment. Analysis of
this cDNA sequence indicated that this second amplification product
included TERT motifs T, 1, 2, A, B', and C. This amplified sequence did
not include the entire mTERT coding sequence. Approximately 800 base
pairs of coding sequence and the 3' untranslated region remained to be
isolated.
[0357] To isolate the remaining 3' end of the mTERT sequence, bacterial
artificial chromosomes (BAC clones) containing genomic mouse DNA were
screened by Southern hybridization using probes designed from hTERT, as
described above. Conventional, low stringency hybridization protocols
were used, together with the probes designated A, B and C, described
above, a clone that positively hybridized to probe C, under selective
conditions, was isolated. Genomic BAC clones (BAC 495-M5 and 145 K20)
were isolated and the inserts subcloned as Pst1 fragments (called mTRT
Pst1, mTRT Pst3, and mTRT 496-2A2). Sequence analysis of these clones
indicated that they included the 3' one third of the mTERT coding
sequence, including the 3' untranslated region (UTR). These inserts
also were found to include mTERT intronic sequence (as noted above, the
insert was derived from genomic BAC clones).
[0358] A RT-PCR product (called mTRT Ra-200) from the cDNA described
above was obtained using primers mTRT.35 (from mTRT Ra3')
(5'-CTTCCTCAGGACCCTGGTCCGAG-3') (SEQ ID NO:9) and mTRT.27 (from mTRT
495-2A2) (5'-ATTGAGGTCTGGGCATACCTGC-3') (SEQ ID NO:10). This reaction
amplified a contaminating DNA encoding a portion of the mTERT gene and
a non-coding region.
[0359] Another DNA containing the 3' end of the mTERT cDNA was obtained
by RT-PCR The primer pair was a 3' primer including the sequence
encoding the carboxy-terminus of hTERT cDNA
(5'-TCAGCGTCGTCCCCGGGAGCTT-3') (SEQ ID NO:11) and a 5' primer from the
above-described upstream mTERT amplification product (mTRT Ra-200)
(5'-TCACCCTCTGAGGCTTCGGTGT-3') (SEQ ID NO:12). These two primers were
reacted with cDNA from mouse poly A<+> RNA. The product of this
amplification was subcloned (into plasmid designated mTRT Ra-62) and
sequenced. Analysis of the sequence showed that it included the
carboxy-terminus encoding portion of the ORF and 3' UTR (from the
transcribed, but untranslated cDNA sequence) and intronic sequences.
[0360] To construct a DNA spanning from pGRN227 to the 3' UTR, cDNA
from mouse testis poly A+ mRNA (Clontech, Palo Alto, Calif.) was
amplified using error-free, Pwo DNA polymerase (Boehringer Mannheim,
Amersterdam, The Netherlands). cDNA was first made using a 3' oligo-dT
primer in a 3' RACE amplification protocol, as generally described
above. Subsequently, the primers mTRT.10 (5'-CGTCGATACTGGCAGATGCGG-3')
(SEQ ID NO:13) and mTRT.53 (5'-GTGCTGAGGCTACAATGCCCATGT-3') (SEQ ID
NO:14) were amplified at 94[deg.] C. for 30 min., 68[deg.] C. for 3
min., for 30 cycles; followed by 30 more cycles using primers mTRT.9
(5'-CTTTTACATCACAGAGAGCAC-3') (SEQ ID NO:15) and mTRT.52
(5'-CATGTTCATCTAGCGGAAGGAGACA-3') (SEQ ID NO:16). The PCR product
(called mTRT Ra-52) was cloned into pCR II (Invitrogen, San Diego,CA),
and 5 independent clones were isolated and the mTERT inserts sequenced
(called mTRT Ra52). The DNA insert sequence was identical for all 5
clones and matched the sequence of the mTERT PCR amplification products
described above, including the entire mTERT open reading frame. A
unique NheI restriction site located in the region of the overlap
between this RT-PCR product (called mTRT Ra 52.17 or pGRN189) and the
5' mTERT cDNA clone was utilized to construct the full length mTERT
ORF. The plasmid with this fill-length ORF was designated pGRN18. The
mTERT insert of pGRN188 (SEQ ID NO:1) has been submitted to Genbank as
Accession No. AF051911 (and is incorporated by reference herein, as
noted below).
[0361] FIG. 1 shows the complete sequence of the mTERT cDNA (SEQ ID
NO:1). FIG. 2 shows the deduced translation (polypeptide) product (SEQ
ID NO:2). FIG. 6 shows a preliminary sequencing of the genomic promoter
region of mTERT (SEQ ID NO:4).
[0362] Cloning and Sequencing of
Genomic mTERT DNA
[0363] A lambda phage (called lambda-mTERT1) with an approximately 23
kilobase pair (Kbp) insert containing the ATG initiator for mTERT was
cloned from a mouse genomic 129SV phage library (Stratagene, San Diego,
Calif.) using a mTERT cDNA probe (residues 1586 to 1970 from SEQ ID
NO:1). Two subfragments of lambda-mTERT1 (an 8 Kbp HindIII and a 6 Kbp
BglII fragment) were found to hybridize to portions of pGRN227 in a
Southern hybridization experiment, see map, FIG. 7. The 8kb HindIII
phage DNA fragment was subcloned into the HindIII site of Bluescript
KS(+) (Stratagene, San Diego, Calif.) (called B2.18). The 6kb BglII
fragment, which begins just downstream of the ATG initiator codon and
extends in the 3' direction, was subcloned into the BamHI site of
Bluescript KS(+) (called pmTERTgen-BglII). A preliminary DNA sequence
of a portion of B2.18 containing the ATG initiator and extending
upstream is shown in FIG. 8 (SEQ ID NO:5). Comparison of the genomic
sequence (FIG. 8) versus the mTERT cDNA sequence (FIG. 1) indicates a
probable 102 bp intron at position 2306 to 2407 (residues as numbered
in FIG. 8). A 104 bp intron is in the analogous position in hTERT.
[0364] Cloning and Sequencing mTERT
Species
[0365] The invention provides isolated, purified, and recombinant genes
for mTERT, including mTERT alleles, homologues, and isoforms. The
invention provides an example of an mTERT nucleic acid and polypeptide
species, SEQ ID NO:1 and SEQ ID NO:2, respectively, and describes the
structural features common to mTERT species that can be to detect and
identify mTERT isoforms, alleles and homologs. The conservation of
these intron sites between mouse and human TERTs predicts that the
first exon constitutes a functional amino acid domain, the alteration
or loss of this domain could effect a change in TERT function. The
invention provides nucleic acid and protein reagents encoding or
comprising this domain which can be used to restore a TERT function to
TERT molecules missing this domain or to provide that function in vitro
or in vivo.
[0366] mTERT nucleic acid sequence (from cDNA of SEQ ID NO:1) and
protein sequence information (SEQ ID NO:2) can be used to prepare PCR
primers and oligonucleotides for the identification of telomerase
gene(s) and cDNA. PCR primers pairs that can amplify sequences
conserved amongst mTERT species are preferred reagents of the invention
and are useful to amplify directly new mTERT isoforms, homologues and
alleles. Alternatively, such oligonucleotides are useful to detect
mTERT-encoding nucleic acid using a variety of hybridization techniques
and conditions. These oligonucleotides can be generated using any known
technique, including PCR, enzymatic restriction digestion of isolated
DNA or organic synthesis. These nucleic acids can be labeled for
detection and hybridized to DNA or RNA by any known technique, as
described above.
[0367] Total RNA can be extracted and enriched for mRNA using the
QuickPrep Micro mRNA Purification Kit (Pharmacia, Piscataway, N.J.)
according to the manufacturer's instructions. The mRNA can then be used
to make cDNA templates by reverse transcription, using, e.g., the avian
myeloblastosis virus (AMV) reverse transcriptase (Pharmacia), as
described by Sambrook. PCR is performed on the cDNA using, for example,
a Techne PHC-3 thermal cycler (Techne, Princeton, N.J.) with any set of
primers with sequence complementary or identical to or based on a known
mTERT, or other TERT, sequence. PCR can also be used to amplify
telomerase sequences from murine genomic DNA. Alternative variations of
traditional PCR can be used, such as RACE, as described above. As noted
above, PCR amplification can use a variety of annealing conditions. For
example, mTERT can be amplified using the following cycling protocol:
denaturing at 94[deg.] C., 45 seconds; annealing at 60[deg.] C., 45
seconds; and extension at 72[deg.] C., 90 seconds. This can be repeated
for a total of about 30 to 40 cycles, yielding a DNA product, which can
be purified. The PCR product can be sequenced by any known technique,
such as the dideoxy-chain termination method using a Dye Terminator
Cycle Sequencing Kit(TM) Ready Reaction Kit (Applied Biosystems, Foster
City, Calif.) and a Model 373A DNA Sequencer (Applied Biosystems). The
PCR product, once identified as an mTERT sequence, can be further
labeled and used as a hybridization probe, as described above.
[0368] Computer databases and programs can be used to analyze the
resultant DNA sequence for its sequence identity, or homology, to known
murine and other related TERT sequences, as described above. For
example, PC/Gene(TM) software (IntelliGenetics Inc., Mountain View,
Calif.) aligns sequences and displays open reading frames. BLAST N and
BLAST D search algorithms can be employed to search the GenBank
database (NIH, Bethesda, Md.) for any matches between the derived mTERT
sequence and known mTERT and other TERT sequences.
Example 2
RNase Protection Assay for Detection
and Quantitation of TERT mRNA
[0369] RNase protection assays can be used to detect, monitor, or
diagnose the presence of an mTERT mRNA or a variant mRNA. An RNase
protection assay is a reliable, sensitive, and quantifiable assay for
detection of mTERT RNA. One illustrative RNase protection probe is an
in vitro synthesized RNA comprised of sequences complementary to mTERT
mRNA sequences and additional, non-complementary sequences. The latter
sequences are included to distinguish the full-length probe containing
these sequences from a probe that has only complementary sequences. In
a positive assay, the complementary sequences of the probe are
protected from RNase digestion, because they are hybridized to mTERT
mRNA. The non-complementary sequences (single-stranded sequences) are
digested away from the probe by the RNase.
[0370] The following illustrative example describes an RNase protection
assay which can be used to detect and quantify mTERT mRNA. Also, see,
e.g., Ma (1996) Methods 10:273-278 and Ausubel (1987) supra, chapter
4.7, for general details on RNase protection assay protocols; Kenrick
(1997) Nucleic Acids Res. 25:2947-2948, describing a method to quantify
mRNA levels using RNase protection and scintillation proximity assay
technologies, a variety of mTERT protection probes can be designed for
use with mouse RNA. The probes can differ in their sequence
complementary to mTERT, but each may contain identical
non-complementary sequences, i.e., derived from the SV40 late mRNA
leader sequence. Probes designed for use in this exemplary RNase
protection assay can be chimerical antisense RNA probes. They can
comprise the initiator G from the T7 promoter, 32 nucleotides of the
SV40 late leader (Chiou (1991) J. Virol. 65:6677-6685) and about 150
nucleotides to about 200 or more nucleotides of antisense mTERT. Using
T7 RNA polymerase and radioactive guanosine, probes can be labeled to
generate probes that are 800,000 cpm/pmol.
[0371] To conduct the assay, either probe can be hybridized to RNA,
i.e., polyA+ RNA, from a test sample. T1 ribonuclease and RNase a are
then added. After RNase digestion, probe RNA is purified and analyzed
by gel electrophoresis.
[0372] RNAse protection probes can be generated by in vitro
transcription using T7 RNA polymerase. Radioactive or otherwise labeled
ribonucleotides can be included for synthesis of labeled probes. The
templates for the in vitro transcription reaction to produce the RNA
probes are PCR products. The illustrative probes described above can be
synthesized using T7 polymerase following PCR amplification of mTERT
DNA using primers that span the corresponding complementary region of
the mTERT gene or mRNA. In addition, the downstream primer contains T7
RNA polymerase promoter sequences and the non-complementary sequences.
[0373] RNase protection probes are hybridized to poly a+ RNA, then
digested with T1 Ribonuclease and RNase a, as described in Ausubel. The
plasmid containing the TERT insert is linearized with restriction
endonuclease. Transcription initiated with T7 RNA polymerase yields a
runoff transcript. Transcripts are quantified by the inclusion of
<35> S UTP in the nucleotide pool (400 cpm/pmol uridine).
Protected probes of the correct length are quantified by comparing them
with known quantities of an in vitro generated standard.
Example 3
Expression of mTERT in Bacteria,
Yeast, Insect and Mammalian Cells
[0374] The following example details the design of mTERT-expressing
bacterial expression vectors to produce large quantities of
full-length, biologically active mTERT (SEQ ID NO:2). Generation of
biologically active mTERT in this manner is useful for telomerase
enzyme reconstitution assays, assaying for telomerase activity
modulators, analysis of the activity of newly isolated species of
telomerase, identifying and isolating compounds which specifically
associate with telomerase, analysis of the activity of telomerase which
has been site-specifically mutated, as described above, to analyze the
secondary, tertiary or quaternary structure of mTERT and telomerase
enzyme, as by crystallization and diffraction analysis or NMR, and as
an immunogen, for example.
[0375] pThioHis a/hTERT Bacterial
Expression Vector
[0376] To produce large quantities of full-length or subfragments of
mTERT (SEQ ID NO:2), the bacterial expression vector pThioHis a
(Invitrogen, San Diego, Calif.) can be used. In one embodiment, the
vector incorporates an mTERT-coding insert including the full-length or
partial sequence encoding mTERT (SEQ ID NO:2). This expression vector
is designed for inducible expression in bacteria.
[0377] The vector can be also induced to express, in E. coli, high
levels of a fusion protein composed of a cleavable, HIS tagged
thioredoxin moiety and the full length or subfragment of the mTERT
protein.
[0378] pGEX-2TK wth mTERT, with HIS-8
Tag
[0379] To produce large quantities of a full length of a fragment of
mTERT, another E. coli expression vector pGEX-2TK (Pharmacia Biotech,
Piscataway N.J.) construct can be used. This construct can contain a
subsequence or all of the mTERT coding sequence (SEQ ID NO:1) and a
sequence encoding eight consecutive histidine residues (HIS-8 Tag).
[0380] Vectors with mTERT cDNA Lacking
5'-non-coding Sequence
[0381] As described above, in one embodiment, the invention provides
for an mTERT that is modified in such a site-specific manner to
facilitate cloning into bacterial, mammalian, yeast and insect
expression vectors without any 5' untranslated mTERT sequence. In some
circumstances, minimizing the amount of non-protein encoding sequence
allows for improved protein production (yield) and increases mRNA
stability. In this embodiment of the invention, the 5' non-coding
region is removed before cloning into the bacterial expression vector.
[0382] This is effected by engineering an additional restriction
endonuclease site just upstream (5') to the start (ATG) codon of mTERT
cDNA. The creation of a restriction site just 5' to the coding region
of the protein allows for design and production of fusion proteins,
including labels and peptide TAGs, for immunodetection and purification.
[0383] Plasmids with mTERT cDNA
Lacking 3'-non-coding Sequence
[0384] As discussed above, the invention provides expression vectors
containing TERT-encoding nucleic acids in which some or all non-coding
sequences have been deleted. In some circumstances, minimizing the
amount of non-protein encoding sequence allows for improved protein
production (yield) and increased mRNA stability. In this embodiment,
the 3' untranslated region of mTERT is deleted before cloning into the
bacterial expression plasmid.
[0385] MPSV-mTERT Expression Plasmids
[0386] The invention also provides for a method of expressing mTERT in
mammalian cells that can give the highest possible expression of
recombinant mTERT without actually modifying the coding sequence (e.g.
optimizing codon usage). In one embodiment, the invention provides MPSV
mammalian expression plasmids (described by Lin J-H (1994) Gene
47:287-292) capable of expressing the mTERTs of the invention. The MPSV
plasmids can be expressed either as stable or transient clones.
[0387] In this expression method, while the mTERT coding sequence (SEQ
ID NO:1) itself is unchanged, exogenous transcriptional control
elements are incorporated into the vector. The myeloproliferative
sarcoma virus (MPSV) LTR (MPSV-LTR) promoter, enhanced by the
cytomegalovirus (CMV) enhancer, is incorporated for transcriptional
initiation. This promoter consistently shows higher expression levels
in cell lines (see Lin J-H (1994) supra), a Kozak consensus sequence
can be incorporated for translation initiation (see Kozak (1996) Mamm.
Genome 7:563-574. All extraneous 5' and 3' untranslated mTERT sequences
can be removed to insure that these sequences do not interfere with
expression, as discussed above.
[0388] The invention also provides for an mTERT "antisense" sequence
containing plasmid. This vector is identical to that described above
except that the mTERT insert is the antisense sequence of mTERT SEQ ID
NO:1.
[0389] Two selection markers, PAC
(Puromycin-N-acetyl-transferase=Puromycin resistance) and HyB
(Hygromycin B=Hygromycin resistance) are present for selection of the
plasmids after transfection (see discussion referring to selectable
markers, above). Double selection using markers on both sides of the
vector polylinker can ensure the stable maintenance of the mTERT coding
sequence, a DHFR (dihydrofolate reductase) encoding sequence can be
included to allow amplification of the expression cassette after stable
clones are made. Other means of gene amplification can also be used to
increase recombinant protein yields.
[0390] The invention also provides MPSV mammalian expression plasmids
containing mTERT fusion proteins. In one embodiment, the mTERT
sequence, while retaining its 5' untranslated region, is linked to an
epitope flag, such as the IBI FLAG (International Biotechnologies Inc.
(IBI), Kodak, New Haven, Conn.) and inserted into the MPSV expression
plasmid. This particular construct contains a Kozak translation
initiation site. The expressed fusion protein can be purified using the
M-1 anti-FLAG octapeptide monoclonal antibody (IBI, Kodak, supra).
[0391] Bacterial Expression Vectors
Using Antibiotic Selection Markers
[0392] The invention also provides bacterial expression vectors that
can contain selection markers to confer a selectable phenotype on
transformed cells and sequences coding for episomal maintenance and
replication such that integration into the host genome is not required.
For example, the marker may encode antibiotic resistance, particularly
resistance to chloramphenicol (see Harrod (1997) Nucleic Acids Res. 25:
1720-1726), kanamycin, G418, bleomycin and hygromycin, to permit
selection of those cells transformed with the desired DNA sequences,
see for example, Blondelet-Rouault (1997) supra; Mahan (1995) Proc.
Natl. Acad. Sci. USA 92:669-673. In one embodiment, the full length
mTERT (SEQ ID NO:1) is cloned into a modified Bluescript plasmid
vector. The mTERT ORF is oriented in the opposite orientation of the
Lac promoter. This makes a plasmid that is suitable for mutagenesis of
plasmid inserts, such as mTERT nucleic acids of the invention. mTERT
can be site-specifically altered, e.g., in motif regions, to create,
e.g., dominant negative mTERT mutants, as described above. This plasmid
can also be used for in vitro transcription of mTERT using the T7
promoter and in vitro transcription of antisense mTERT using the T3
promoter.
Expression of mTERT Telomerase in Yeast
[0393] The invention provides mTERT-expressing yeast expression vectors
to produce large quantities of full-length, biologically active mTERT,
or fragments thereof including the mTERT polypeptide comprising a
sequence as set forth in SEQ ID NO:2.
[0394] Pichia pastoris Expression
Vector
[0395] To produce large quantities of full-length, biologically active
mTERT (SEQ ID NO:2), or a fragment thereof, the Picha pastoris
expression vector pPICZ B (Invitrogen, San Diego, Calif.) can be used.
The mTERT-coding insert is derived from SEQ ID NO:1. This nucleotide
sequence encodes a polypeptide comprising the full-length sequence of
mTERT as set forth in SEQ ID NO:2. This expression vector is designed
for inducible expression in P. pastoris of high levels of full-length,
unmodified mTERT protein, or a fragment thereof (SEQ ID NO:2).
Expression is driven by a yeast promoter, but the expressed sequence
utilizes the mTERT initiation and termination codons. The pPICZ B/hTERT
vector (Invitrogen, San Diego, Calif.) is used to transform the yeast.
Expression of mTERT in Insect Cells
[0396] The following example details the design of TERT-expressing
insect cell expression vectors to produce large quantities of
full-length, biologically active TERT, such as mTERT (SEQ ID NO:2), or
subfragments thereof.
[0397] Baculovirus Expression Vector
pBlueBacHis2 B
[0398] mTERT coding sequence can be cloned into the baculovirus
expression vector pVL1393 (Invitrogen, San Diego, Calif.). This
construct is subsequently cotransfected into Spodoptera fungupeida
(sf-9) cells with linearized DNA from Autograph California nuclear
polyhidrosis virus (Baculogold-AcMNPV). The recombinant baculoviruses
obtained are subsequently plaque purified and expanded following
published protocols, as discussed above. This expression vector is
designed for expression in insect cells of high levels of full-length
mTERT protein, or subfragments thereof. Expression is driven by a
baculoviral polyhedrin gene promoter, but the expressed sequence
utilizes the mTERT initiation and termination codons.
[0399] To produce large quantities of full-length, biologically active
mTERT (SEQ ID NO:2), or subfragments thereof, the baculovirus
expression vector pBlueBacHis2 B (Invitrogen, San Diego, Calif.) can be
used. The mTERT-coding insert can comprise nucleotides as set forth in
SEQ ID NO:1. This nucleotide sequence includes the full-length sequence
encoding mTERT (SEQ ID NO:2).
[0400] Another embodiment provides for a full length mTERT with 6HIS
and Anti-Xpress tags. This vector also contains an insert consisting of
all or a subsequence of SEQ ID NO:1. The vector directs expression in
insect cells of high levels of full length mTERT, or fragments thereof,
fused to cleavable 6-histidine and an Anti-Xpress tags with an
enterokinase cleavage site.
[0401] Baculovirus Expression Vector
pBlueBac4.5
[0402] To further produce large quantities of full-length, biologically
active mTERT (SEQ ID NO:2), or subfragments thereof, a second
baculovirus expression vector, pBlueBac4.5 (Invitrogen, San Diego,
Calif.) can be used. The mTERT-coding insert can also consist of
nucleotides comprising all or a subsequence of SEQ ID NO:1.
[0403] Baculovirus Expression Vector
pMelBacB
[0404] To further produce large quantities of full-length, biologically
active mTERT (SEQ ID NO:2), or sub fragments thereof, a third
baculovirus expression vector, pMelBacB (Invitrogen, San Diego, Calif.)
can be selected. The mTERT-coding insert can also consist of
nucleotides comprising all or a subsequence of SEQ ID NO:1.
[0405] pMelBacB can direct expression of full length mTERT, or
subfragments thereof (SEQ ID NO:2), in insect cells to the
extracellular medium through the secretory pathway using the melittin
signal sequence. High levels full length mTERT (SEQ ID NO:2) are thus
secreted. The melittin signal sequence is cleaved upon excretion, but
is part of the protein pool that remains intracellular.
Expression of mTERT in Mammalian Cells
[0406] The recombinant mTERT of the invention can be produced in large
quantities as full-length, biologically active mTERT, or subfragments
thereof (SEQ ID NO:2), in a variety of mammalian cell lines.
[0407] mTERT Expressed in 293 Cells
using Episomal Vector pEBVHis
[0408] In one embodiment, an episomal vector, pEBVHis (Invitrogen, San
Diego, Calif.) engineered to express an mTERT (SEQ ID NO:2) fusion
protein comprising mTERT fused to an N-terminal extension epitope tag,
the Xpress epitope (Invitrogen, San Diego, Calif.). The mTERT open
reading frame (ORF) is cloned so that the mTERT ORF, or subfragments
thereof, are in the same orientation as the Rous Sarcoma virus (RSV)
promoter. In this orientation, the His6 flag is relatively closer to
the N-terminus of mTERT, a control vector can also be constructed to
contain as an insert the antisense sequence of the fusion protein
(mTERT and the epitope tag), for co-transfection, to be used as a
negative control.
[0409] The vectors are transfected into mammalian cells, and translated
mTERT is identified and isolated using an antibody specific for the
Xpress epitope. pEBVHis is a hygromycin resistant EBV episomal vector
that expresses the protein of interest fused to an N-terminal peptide.
Cells carrying the vector are selected and expanded, then nuclear and
cytoplasmic extracts prepared. These and control extracts are
immunoprecipitated with anti-Xpress antibody, and the
immunoprecipitated beads are tested for mTERT and/or telomerase enzyme
expression and activity by the various assays described above.
Expression of Recombinant mTERT in
Mortal, Normal Diploid Human or Mouse Cells
[0410] In one embodiment of the invention, recombinant mTERT and
necessary telomerase enzyme complex components can be expressed in
normal, diploid mortal cells to create an indefinitely proliferating
cell line, to directly immortalize the cells, or to facilitate
immortalizing them. This allows one to obtain diploid immortal cells
with an otherwise normal phenotype and karyotype.
[0411] Sense mTERT (SEQ ID NO:1) and antisense mTERT (complementary to
SEQ ID NO:1) are cloned into a CMV vector. These vectors are purified
and transiently transfected into two normal, mortal, diploid mammalian
cell clones. Analysis of telomerase enzyme activity can be done using a
TRAP assay, as described above, e.g., utilizing the TRAPezc Kit (Oncor,
Inc., Gaithersburg, Md.). Transfection of sense mTERT-but not antisense
mTERT-generates telomerase enzyme activity.
[0412] Vectors for Regulated
Expression of mTERT in Mammalian Cells: Inducible and Repressible
Expression of mTERT
[0413] The invention provides vectors which can be manipulated to
induce or repress the expression of the mTERT of the invention. For
example, mTERT (SEQ ID NO:1) is cloned into the Ecdysone-Inducible
Expression System from Invitrogen (San Diego, Calif.) and the Tet-On
and Tet-off tetracycline regulated systems from Clontech Laboratories,
Inc. (Palo Alto, Calif.). Such inducible expression systems are
provided for use in the methods of the invention where it is important
to control the level or rate of transcription of transfected mTERT. For
example, the invention provides cell lines made indefinitely
proliferating or immortalized through the expression of mTERT; such
cells can be rendered "mortal" by inhibition of mTERT expression by the
vector through its transcriptional controls, such as the Tet-Off
system. The invention also provides methods of expressing mTERT only
transiently to avoid the constitutive expression of mTERT, which may
lead to unwanted "immortalization" of transfected cells, as discussed
above.
[0414] The Ecdysone-Inducible Mammalian Expression System is designed
to allow regulated expression of the gene of interest, such as mTERT,
in mammalian cells. The system is distinguished by its tight regulation
that allows almost no detectable basal expression and greater than
200-fold inducibility in mammalian cells. The expression system is
based on the heterodimeric ecdysone receptor of Drosophila. The
Ecdysone-Inducible Expression System uses a steroid hormone ecdysone
analog, muristerone a, to activate expression of mTERT via a
heterodimeric nuclear receptor. Expression levels have been reported to
exceed 200-fold over basal levels with no effect on mammalian cell
physiology (No (1996) "Ecdysone-Inducible Gene Expression in Mammalian
Cells and Transgenic Mice" Proc. Natl. Acad. Sci. USA 93, 3346-3351).
Once the receptor binds ecdysone or muristerone, an analog of ecdysone,
the receptor activates an ecdysone-responsive promoter to give
controlled expression of the gene of interest, as mTERT. In the
Ecdysone-Inducible Mammalian Expression System, both monomers of the
heterodimeric receptor are constitutively expressed from the same
vector, pVgRXR. The ecdysone-responsive promoter, which ultimately
drives expression of the gene of interest, is located on a second
vector, pIND, which drives the transcription of the gene of interest.
In one embodiment, mTERT is cloned in the pIND vector (Clontech
Laboratories, Inc, Palo Alto, Calif.) containing five modified ecdysone
response elements (E/GREs) upstream of a minimal heat shock promoter
and the multiple cloning site. The construct is then transfected in
cell lines which have been pre-engineered to stably express the
ecdysone receptor. After transfection, cells are treated with
muristerone a to induce intracellular expression of the gene of
interest from pIND.
[0415] The Tet-on and Tet-off expression systems (Clontech, Palo Alto,
Calif.) give access to the regulated, high-level gene expression
systems described by Gossen (1992) "Tight control of gene expression in
mammalian cells by tetracycline responsive promoters" Proc. Natl. Acad.
Sci. USA 89:5547-5551, for the Tet-Off transcription repression system;
and Gossen (1995) "Transcriptional activation by tetracycline in
mammalian cells" Science 268:1766-1769, for the Tet-On inducible
transcriptional system. In "Tet-Off" transformed cell lines, gene
expression is turned on when tetracycline (Tc) or doxycycline ("Dox;" a
Tc derivative) is removed from the culture medium. In contrast,
expression is turned on in Tet-On cell lines by the addition of Tc or
Dox to the medium. Both methods permit expression of cloned genes to be
regulated closely in response to varying concentrations of Tc or Dox.
This method uses the "pTRE" as a response plasmid that can be used to
express a gene of interest, such as mTERT. pTRE contains a multiple
cloning site (MCS) immediately downstream of the Tet-responsive
PhCMV*-1 promoter. cDNAs or genes of interest inserted into one of the
sites in the MCS will be responsive to the tTA and rtTA regulatory
proteins in the Tet-Off and Tet-On systems, respectively. PhCMV*-1
contains the Tet-responsive element (TRE), which consists of seven
copies of the 42-bp tet operator sequence (tetO). The TRE element is
just upstream of the minimal CMV promoter (PminCMV), which lacks the
enhancer that is part of the complete CMV promoter in the pTet
plasmids. Consequently, PhCMV*-1 is silent in the absence of binding of
regulatory proteins to the tetO sequences. The cloned insert must have
an initiation codon. In some cases, addition of a Kozak consensus
ribosome binding site may improve expression levels; however, many
cDNAs have been efficiently expressed in Tet systems without the
addition of a Kozak sequence. pTRE-Gene X plasmids are cotransfected
with pTK-Hyg to permit selection of stable transfectants.
[0416] Setting up a Tet-Off or Tet-On expression system generally
requires two consecutive stable transfections to create a
"double-stable" cell line that contains integrated copies of genes
encoding the appropriate regulatory protein and TERT under the control
of a tet-responsive element (TRE). In the first transfection, the
appropriate regulatory protein is introduced into the cell line of
choice by transfection of a "regulator plasmid" such as pTet-Off or
pTet-On vector, which express the appropriate regulatory proteins.
mTERT cloned in the pTRE "response plasmid" is then introduced in the
second transfection to create the double-stable Tet-Off or Tet-On cell
line. Both methods give very tight on/off control of gene expression,
regulated dose-dependent induction, and high absolute levels of gene
expression.
Expression of Recombinant mTERT with
DHFR and Adenovirus Sequences
[0417] In one embodiment, a plasmid construct is prepared for transient
expression of mTERT cDNA in mammalian cells, a Kozak consensus is
inserted at the 5' end of mTERT coding sequence. The mTERT insert can
be designed to contain no 3' or 5' UTR. The mTERT cDNA is inserted into
the EcoRI site of p91023(B) (Wong (1985) Science 228:810-815). The
mTERT insert is in the same orientation as the DHFR ORF. The expression
vector is useful for transient expression.
[0418] The selected plasmid contains an SV40 origin and enhancer just
upstream of an adenovirus promoter, a tetracycline resistance gene, an
E. coli origin and an adenovirus VAI and VAII gene region. This
expression cassette contains, in the following order: the adenovirus
major late promoter, the adenovirus tripartite leader, a hybrid intron
consisting of a 5' splice site from the first exon of the tripartite
leader and a 3' splice site from the mouse immunoglobulin gene; the
mTERT cDNA; the mouse DHFR coding sequence; and the SV40
polyadenylation signal.
[0419] The adenovirus tripartite leader and the VA RNAs have been
reported to increase the efficiency with which polycistronic mRNAs are
translated. DHFR sequences have been reported to enhance the stability
of hybrid mRNA. DHFR sequences also can provide a marker for selection
and amplification of vector sequences. See Logan (1984) Proc. Natl.
Acad. Sci. USA 81:3655); Kaufman (1985) Proc. Natl. Acad. Sci. USA 82:
689; and Kaufman (1988) Focus (Life Technologies, Inc.) Vol. 10, no. 3).
Example 4
mTERT Transgenic Mice and mTERT "Knock
Out" Mice
[0420] The invention provides transgenic cells and animals which can
express an introduced recombinant mTERT. The recombinant mTERT can be
wild-type (native) or modified. An exogenous mTERT endogenous mTERT can
remain function. The methods of the invention include screening for
mTERT modulators in animals by reconstituting an mTERT and/or murine
telomerase enzyme in an animal, e.g., a transgenic animal.
[0421] The in vivo assays methods include "knockout" models, in which
one or several units of the endogenous telomerase, telomerase RNA
moiety and/or telomerase-associated proteins have first been deleted or
inhibited before an exogenous murine telomerase activity (full or
partial) is reconstituted. The transgenic animals of the invention also
provide methods of expressing the mTERT and murine telomerase
compositions of the invention and providing indefinitely proliferating
and immortalized, otherwise normal cells which can be used to express
compositions of interest.
[0422] The mTERT gene can be "knocked out" using conventional
techniques, usually involving homologous recombination, as discussed
above. Thus, the invention provides for a unique targeting vector
comprising the mTERT nucleic acid sequences of the invention, including
at least part of SEQ ID NO:1, for use in homologous recombination to
create a mouse that cannot express its endogenous mTERT. The targeting
vector is usually inserted in a pluripotential embryonic cell or cell
line, such as mouse embryonic stem (ES) cells, to disrupt the
complementary endogenous gene by homologous recombination. Animals with
the targeted and disrupted gene of interest, lacking or having impaired
ability to express that gene, are bred.
[0423] Means of constructing such vectors, inserting them into the
cells of interest, breeding animals, and the like, to construct these
"knock-out" animals are described herein, and generally well described
in the scientific and patent literature, see also, e.g., U.S. Ser. No.
08/623,166, filed 28 Mar. 1996, describing construction of hTERC (hTR)
knockout mice. See also, e.g., for further illustrative examples of
construction of "knockout mice," Ma (1997) J. Clin. Invest.
100:957-962; Schwindinger (1997) Endocrinology 138:4058-4063; Stenbit
(1997) Nat. Med. 3:1096-1101; Moreadith (1997) J. Mol. Med. 75:208-216;
Udy (1997) Exp. Cell Res. 231:296301, describing use of isogenic lines
to support homologous recombination events; Taghian (1997) Mol. Cell.
Biol. 17:638&6393, on use of chromosomal double-strand breaks to
induce gene conversion, chromosomal and extrachromosomal recombination,
and gene targeting at high frequency in mammalian cells; Templeton
(1997) Gene Ther. 4:700-709, for methods to improve the efficiency of
gene correction in mouse embryonic stem cells using homologous
recombination; Araki (1997) Nucleic Acids Res. 25:868-872; describing
targeted, site-directed integration of DNA using mutant lox sites in
embryonic stem cells; and, Kühn (1997) Curr. Opin. Immunol.
9:183-188, describing methods for site-specific and homologous DNA
recombination expanding the potential of gene targeting in embryonic
stem cells.
[0424] Plasmid Construction and
Production of Transgenic Mice
[0425] The construction and use of transgenic mice that express
introduced mTERT, hTERT, or TERT genes is described below.
[0426] EcoRI cDNA fragments containing the full length ORF for mTERT
(from pGRN188), hTERT (from pGRN121), and hTERT-D868A (from pGRN202)
were ligated into the pCAGGS expression vector containing the chicken
beta-actin promoter, cytomegalovirus enhancer element, beta-actin
intron and bovine globin poly-adenylation signal (Niwa (1991) Gene
108:193-199). The entirety of each insert with promoter, coding, and
polyadenylation sequences were liberated with HinDIII and SalI
restriction digests, gel purified, and then injected into C57 BL/6*FVB
fertilized eggs (general procedure described in Morgenbesser (1995)
EMBO J. 14:743-746). The DNA injected eggs were then transplanted to
pseudopregnant female mice resulting in 26 newborns. Incorporation of
the transgene was identified by Southern and slot blot analysis using
mTERT cDNA fragment probes. Three transgene positive founder lines were
identified.
[0427] Construction of mTERT Gene
Knockout Mice
[0428] The construction of a transgenic mouse line homozygous for an
mTERT deletion is described below, this mouse line is also called a
"knockout" mouse line in that it is missing functional copies of both
mTERT alleles (the invention also provides for mice in which mTERT
expression is modified, or in which only one allele of mTERT is deleted
or modified, as discussed above). The mTERT -/- mouse knockout line can
be used to assess mTERT, hTERT, telomerase, and telomere maintenance
and function in vivo or ex vivo. Mutated or deleted forms of TERT genes
can be also introduced into the mTERT -/- cells or mice to create new
transgenic mice or cells that can assess the functional consequences of
the alterations. In this manner functional domains of TERT can be
identified and their functions assigned. The restoration or loss of
functions associated with TERT alterations could identify TERT- or
telomerase-interacting proteins.
[0429] In another embodiment, the mTERT -/- mice are used to assess in
vivo or ex vivo effects of telomerase inhibitory compounds on animals,
tissues and cells in the absence of telomerase enzyme activity. This is
a useful biological model method to assess the pharmacokinetics and
potential for adverse side effects of telomerase enzyme modulators
(e.g., mTERT inhibitory compounds). Transgenic knockout mTERT -/- lines
with introduced mutant TERTs could be used to assess the in vivo or ex
vivo mode of action of telomerase enzyme modulating compounds and to
improve their agonist, inhibitory or interaction properties.
[0430] The invention also provides cells and mouse lines in which a
recombinant TERT gene with alterations to a transcriptional regulatory
region (e.g., the promoter or other region) in place of a TERT genomic
sequence (e.g., optionally mTERT or hTERT) is reintroduced into the
mTERT -/- mice to assess cis-acting (e.g., promoter) or other
regulatory regions. These mouse lines can also be used to assess the
biological consequences of regulatory region alterations or the
inappropriate expression of the introduced TERT under the control of
the modified regulatory region. These methods can also be used to
assess, alter, or improve the in vivo or ex vivo actions of TERT
affecting trans-activating transcriptional regulatory agents. Such a
method can modulate the expression of the TERT promoter in order to,
e.g., assert a therapeutic effect.
[0431] The mouse mTERT 5' genomic region described above was isolated
by screening a 129/Sv mouse genomic library (Stratagene, San Diego,
Calif.) with a fragment spanning nucleotides 1585-1970 of the mTERT
cDNA (SEQ ID NO:1). The targeting construct, pmTERTKO, utilized the
mutant neomycin-resistance and HSV thymidine kinase genes under the
control of the PKG promoter, and was constructed as generally described
in Serrano (1996) Cell 85:27-37. FIG. 9 presents a schematic
illustration of the targeting construct (vector) pmTERTKO.
[0432] To construct the targeting construct (vector) an approximately
2.8 Kbp EcoRI to XbaI fragment of B2.18 (discussed above), designated
Arm1, was ligated into pPNT (described by Serrano (1996) supra)
downstream of the Neo gene and upstream of the thymidine kinase gene
(FIG. 9). The 6 Kbp BglII fragment, designated Arm2 (FIG. 9), was
excised from pmTERTgen-BglII with NotI and XhoI and ligated into these
sites in pPNT upstream of the Neo gene.
[0433] The pmTERTKO vector was linearized by NotI prior to being
electroporated into WW6 ES cells (Ioffe (1995) Proc. Natl. Acad. Sci.
USA 144:500-510). Homologous recombination of the targeting construct
pmTERTKO into the mTERT gene results in replacement of approximately
600 base pairs (bp) of the mTERT genomic sequence encompassing the ORF
initiating methionine by the construct's neomycin resistance gene.
[0434] Upon transfection into the mouse ES cells and homologous
recombination of the construct, the initiator methionine of mTERT was
replaced by a portion of the pmTERTKO vector sequence, resulting in a
"null" or "knocked-out" allele construct. Clones in which homologous
recombination has occurred are selected for with G418 (150 mg/ml active
component) and 2 mM gancyclovir. mTERT heterozygous ES clones were
identified by Southern blot analysis for the presence of integrated
pmTERTKO vector sequence (the null allele). Positive clones were
subsequently injected into C57BL/6 blastocysts. Resultant male chimeras
with greater than 50% ES contribution, as judged by coat color, were
mated with C57BL/6 females. Germline transmission to agouti offspring
was confirmed by both Southern blot and PCR analysis of tail DNA for
the presence of the integrated vector sequence (the null allele).
[0435] The utility of a mTERT knockout mouse line results from the loss
or modification of telomerase activity associated with the gene
deletions or modifications. Homozygous deletion knockout mice and
progeny will have no telomerase activity since no functional mTERT
protein will be produced. The telomeres of these homozygous mTERT-mice
will progressively shorten, placing an upper limit on the replicative
lifespan of its cells, dependent on their telomere length and telomere
shortening rate. As observed with the mTERC (mTR) knockout mice (Blasco
(1997) Cell 91:25-34) the first generation mice will be fertile.
Subsequent generations will have shorter and shorter telomeres.
Eventually the progressive shortening will result in functional
impairment of chromosomes, leading to infertility. Impairment of
tissues with high proliferative capacity to replace their cells through
cell division is also seen. The rate of telomere shortening in mTERC
-/- mice (lacking telomerase enzyme activity) resulted in fertility and
cell replacement problems in 4 to 6 generations. mTERT -/- mice, also
lacking telomerase enzyme activity, will also have similar defects. The
mTERT -/- mice are distinguishable from mTERC -/- mice in that mTERC
-/- mice retain the ability to express a potentially active mTERT
protein which can interact with telomere proteins, chromosomal
structures, other nucleic acid moieties, regulatory proteins, and the
like. Thus, even in the absence of mTERC, mTERT can modulate telomere
structure and function outside of its telomere addition function. Loss
of these functions in the mTERT -/- mice could, in some circumstances,
lead to more rapid telomere loss, altered telomere or chromosome
function, altered cell cycle regulation, and the like. This could lead
to the inviability of the first generation of mTERT -/- mice, a more
rapid occurrence of the phenotypes observed in the mTR -/- mice, or new
phenotypes.
[0436] In one embodiment, the mTERT -/- mice are mated with the mTR -/-
mice to create a double knockout line missing both mTERT protein and
the mouse telomerase RNA, mTERC. This is a mouse line or cell line with
a "clean" background useful for the simultaneous assessment of TERT and
telomerase RNA functions. Altered mTERTs, hTERTs, mTERCs, and hTERCs
are introduced to assess the functional in vivo and ex vivo affects of
the alterations. These lines are particularly useful for assessing the
structure and function of hTERT and hTERC since a similar in vivo or ex
vivo model method in humans or human cells is technically difficult or
ethically impossible. Regions of TERT and TERC interactions can be
identified and assigned functions. These lines also provide means to
determine how telomerase or TERT modulators affect hTERT and hTERC in
vivo. The method is used to improve the telomerase modulatory (e.g.,
inhibitory) properties of compounds affecting human telomerase. The
method can also be used to assess, and reduce, unwanted or secondary
(side) effects of modulatory compounds in the context of a whole animal.
Example 5
Antibodies Directed to mTERT and Mouse
Telomerase
[0437] The antibodies of the invention can be used in several
embodiments of the invention as described above, including, e.g.: the
isolation of mTERT, murine telomerase enzyme, telomerase-associated
proteins; inhibition of telomerase activity by binding to telomerase;
identifying the location of telomerase in situ.
[0438] mTERT protein fragments to be used as immunogens are generated
using expression vectors, typically bacterial expression vectors.
Specifically, in one embodiment, an E. coli expression vector pGEX-2TK
(Pharmacia Biotech, Piscataway N.J.) construct is used containing
various subfragments of mTERT-encoding nucleic acid sequences (cDNA,
SEQ ID NO:1). The isolated or purified fusion proteins are used in
conventional protocols, as described above, to generate rabbit
polyclonal antisera and mouse polyclonal antisera and monoclonal
antibodies, or to screen phage display libraries, as discussed above.
Example 6
mTERT Telomerase Promoter Expression
Constructs
[0439] The present invention also provides methods and reagents
relating to cis-acting transcriptional and translational mTERT
regulatory elements. Examples of cis-acting transcriptional regulatory
elements include promoters and enhancers of the mTERT gene. The
identification and isolation of cis- and trans-acting regulatory agents
provide further methods and reagents for identifying additional agents
that modulate transcription and translation of mTERT.
[0440] The present invention also provides recombinant vectors in which
an mTERT promoter is operably linked to a reporter gene. Such
constructs are useful, inter alia, in screens to find agents that
modulate the activity of the promoter of the TERT gene. In one
illustrative embodiment, the reporter gene is alkaline phosphatase and
is derived from the well known pSEAP2 reporter gene system (marketed by
Clontech, Palo Alto, Calif.). In one embodiment, to assess the ability
of the mTERT promoter to drive transcription, the mTERT promoter is
fused to the coding sequence of the human secreted alkaline phosphatase
(SEAP).
[0441] SEAP is a secreted form of human placental alkaline phosphatase
(Berger (1988) "Secreted placental alkaline phosphatase: a powerful new
quantitative indicator of gene expression in eukaryotic cells" Gene 66:
1-10; Bronstein (1996) Clin. Chem. 42:1542-1546). This fusion
protein-expressing construct can be inserted into any mammalian
expression vector for transient transfection into cells. The SEAP
reporter gene encodes a truncated form of the placental enzyme which
lacks the membrane anchoring domain, thereby allowing the protein to be
secreted efficiently from transfected cells. Levels of SEAP activity
detected in the culture medium have been shown to be directly
proportional to changes in intracellular concentrations of SEAP mRNA
and protein (Berger (1988) Gene, supra; Cullen (1992) "Secreted
placental alkaline phosphatase as a eukaryotic reporter gene" Methods
Enzymol. 216:362-368). Thus, there is a direct correlation between
levels of SEAP secreted and the activity of the mTERT promoter using
such constructs of the invention.
[0442] Other embodiments include additional mTERT promoter/reporter
protein constructs to evaluate mTERT promoter activity in different
cells under varying conditions. Such reporter proteins include, e.g.,
firefly luciferase, beta-glucuronidase, beta-galactosidase,
cloramphenicol acetyl-transferase, and GFP.
Example 7
In Vitro Reconstitution of Telomerase
Activity with mTERT
[0443] To demonstrate that mTERT cDNA (SEQ ID NO:1) encodes mTERT
catalytic activity, in vitro telomerase enzyme reconstitution assays
can be performed, as described, e.g., by Weinrich (1997) supra. mTERT
was expressed alone or in combination with hTERC, i.e., the
mTERT-containing telomerase enzyme was reconstituted using hTERC as the
RNA moiety. Resultant telomerase activity was measured by a modified
version of the TRAP assay, as described by Kim (1994) supra. As a
positive control, parallel assays were performed with hTERT and hTERC.
An RNase sensitive 6 bp ladder was generated by mTERT in the presence
of hTERC, but not in its absence, indicating that the recombinant mTERT
was transcribed and translated, and telomerase enzyme activity was
reconstituted, and an RNA moiety was necessary for reconstitution of
telomerase enzymatic activity.
[0444] TRAP activity was not seen with the mTERT mutant, mTERTDT, which
lacks the telomerase specific T motif. These in vitro reconstitution
studies demonstrate that the mTERT cDNA encodes telomerase
RNA-dependent catalytic activity and, similar to the human enzyme, the
presence of the T motif is essential for enzymatic catalysis.
[0445] These studies also demonstrate that mTERT and hTERC can form a
functional ribonucleoprotein complex despite species differences in the
telomerase enzyme RNA moieties, including a longer template for hTERC
(see Feng (1995) Science 269:1236-41; Blasco (1995) Science
269:1267-70). This result suggests that, within the context of this in
vitro assay, these primary nucleotide sequence differences in these
telomerase RNA moieties do not impact on higher order RNA structure and
mTERT protein-RNA interactions.
[0446] This example describes three mutants of mTERT which are
predicted to be deficient in a telomerase activity. These mutations
change amino acids in the conserved RT motifs previously shown to be
essential for RT function (Lingner (1997) supra). The mutations are
created using the procedures described in Weinrich (1997) supra.
[0447] Four point mutants are generated in mTERT using pGRN190 as the
mutagenesis vector. Plasmid pGRN190 is a mammalian expression vector
comprising the entire cDNA insert from pGRN188, such that mTERT mRNA is
transcribed from the MPSV (myeloproliferative sarcoma virus) promoter.
The construction of pGRN190 was similar to that used to construct
plasmid pGRN145, described by Bodner, et al., Science, January 1998,
vol. 279:349-352.
[0448] Mutants (1) to (3) are predicted to be deficient in a telomerase
enzyme activity. Oligonucleotide (oligo) sequences for generating these
point mutants are listed below with the position (based on SEQ ID NO:1
residue numbering) and restriction enzyme sites generated indicated in
standard form:
[0449] (1) mF550A (5'-ACAGCTGCTTAGATCTTTCGCTTACATCACAGA-3') (SEQ ID
NO:17). This oligo generates a point mutation that changes the second
phenylalanine in motif T to an alanine (analogous to the F651A in
hTERT). This mutation is predicted to greatly or completely reduce a
telomerase activity. A BglII restriction site is also introduced.
[0450] (2) mD701A (5'-TTGTTAAGGCAGCTGTGACCGGTGCCTATGATGCC-3') (SEQ ID
NO:18). This oligo generates a point mutation that changes the
aspartate to an alanine in motif A (analogous to the D712A in hTERT).
This mutation is predicted to greatly or completely reduce a telomerase
activity. PvuII and AgeI restriction sites are also introduced.
[0451] (3) mD860A (5'-TACGTTTTGTTGCTGACTTTCTACTAGTGACGCCTCAC-3') (SEQ
ID NO:19). This oligo generates a point mutation that changes the
aspartate to an alanine in motif C (analogous to the D868A in hTERT).
This mutation is predicted to greatly or completely reduce a telomerase
activity. A SpeI restriction site is also introduced.
[0452] (4) mD600A (5'-GGCATCACCAGGCCACGTGGCTGGCCATGCCCATC-3') (SEQ ID
NO:20). This oligo generates a point mutation that changes an aspartate
to an alanine upstream of motif 1. This aspartate residue is not
conserved between mTERT and hTERT making a good control base change. No
or little phenotypic result is expected. A PmlI restriction site is
also introduced and a NheI restriction site is deleted.
[0453] It is understood that the examples and embodiments described
herein are for illustrative purposes only and that various
modifications or changes in light thereof will be suggested to persons
skilled in the art and are to be included within the spirit and purview
of this application and scope of the appended claims. All publications,
patents, patent applications, and GenBank sequences cited herein are
hereby incorporated by reference for all purposes.
# SEQUENCE LIS
#TING
(1) GENERAL INFORMATION:
(iii) NUMBER OF SEQUENCES: 101
(2) INFORMATION FOR SEQ ID NO:1:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 3496 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..3496
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
trascriptas
#e (mTRT) cDNA clone"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 10..3435
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) cDNA"
(ix) FEATURE:
(A) NAME/KEY: CDS
(B) LOCATION: 39..3404
(D) OTHER INFORMATION:
#/product= "mouse telomerase reverse
transcripta
#se (mTRT)"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:
GAATTCCGGG TGGGAGGCCC ATCCCGGCCT TGAGCACA ATG ACC CGC
# GCT CCT 53
#
# Met Thr Arg Ala Pro
#
# 1
# 5
CGT TGC CCC GCG GTG CGC TCT CTG CTG CGC A
#GC CGA TAC CGG GAG GTG 101
Arg Cys Pro Ala Val Arg Ser Leu Leu Arg S
#er Arg Tyr Arg Glu Val
10
# 15
# 20
TGG CCG CTG GCA ACC TTT GTG CGG CGC CTG G
#GG CCC GAG GGC AGG CGG 149
Trp Pro Leu Ala Thr Phe Val Arg Arg Leu G
#ly Pro Glu Gly Arg Arg
25
# 30
# 35
CTT GTG CAA CCC GGG GAC CCG AAG ATC TAC C
#GC ACT TTG GTT GCC CAA 197
Leu Val Gln Pro Gly Asp Pro Lys Ile Tyr A
#rg Thr Leu Val Ala Gln
40
# 45
# 50
TGC CTA GTG TGC ATG CAC TGG GGC TCA CAG C
#CT CCA CCT GCC GAC CTT 245
Cys Leu Val Cys Met His Trp Gly Ser Gln P
#ro Pro Pro Ala Asp Leu
55
# 60
# 65
TCC TTC CAC CAG GTG TCA TCC CTG AAA GAG C
#TG GTG GCC AGG GTT GTG 293
Ser Phe His Gln Val Ser Ser Leu Lys Glu L
#eu Val Ala Arg Val Val
70
# 75
# 80
# 85
CAG AGA CTC TGC GAG CGC AAC GAG AGA AAC G
#TG CTG GCT TTT GGC TTT 341
Gln Arg Leu Cys Glu Arg Asn Glu Arg Asn V
#al Leu Ala Phe Gly Phe
90
# 95
# 100
GAG CTG CTT AAC GAG GCC AGA GGC GGG CCT C
#CC ATG GCC TTC ACT AGT 389
Glu Leu Leu Asn Glu Ala Arg Gly Gly Pro P
#ro Met Ala Phe Thr Ser
105
# 110
# 115
AGC GTG CGT AGC TAC TTG CCC AAC ACT GTT A
#TT GAG ACC CTG CGT GTC 437
Ser Val Arg Ser Tyr Leu Pro Asn Thr Val I
#le Glu Thr Leu Arg Val
120
# 125
# 130
AGT GGT GCA TGG ATG CTA CTG TTG AGC CGA G
#TG GGC GAC GAC CTG CTG 485
Ser Gly Ala Trp Met Leu Leu Leu Ser Arg V
#al Gly Asp Asp Leu Leu
135
# 140
# 145
GTC TAC CTG CTG GCA CAC TGT GCT CTT TAT C
#TT CTG GTG CCC CCC AGC 533
Val Tyr Leu Leu Ala His Cys Ala Leu Tyr L
#eu Leu Val Pro Pro Ser
150
#155
#160
#165
TGT GCC TAC CAG GTG TGT GGG TCT CCC CTG T
#AC CAA ATT TGT GCC ACC 581
Cys Ala Tyr Gln Val Cys Gly Ser Pro Leu T
#yr Gln Ile Cys Ala Thr
170
# 175
# 180
ACG GAT ATC TGG CCC TCT GTG TCC GCT AGT T
#AC AGG CCC ACC CGA CCC 629
Thr Asp Ile Trp Pro Ser Val Ser Ala Ser T
#yr Arg Pro Thr Arg Pro
185
# 190
# 195
GTG GGC AGG AAT TTC ACT AAC CTT AGG TTC T
#TA CAA CAG ATC AAG AGC 677
Val Gly Arg Asn Phe Thr Asn Leu Arg Phe L
#eu Gln Gln Ile Lys Ser
200
# 205
# 210
AGT AGT CGC CAG GAA GCA CCG AAA CCC CTG G
#CC TTG CCA TCT CGA GGT 725
Ser Ser Arg Gln Glu Ala Pro Lys Pro Leu A
#la Leu Pro Ser Arg Gly
215
# 220
# 225
ACA AAG AGG CAT CTG AGT CTC ACC AGT ACA A
#GT GTG CCT TCA GCT AAG 773
Thr Lys Arg His Leu Ser Leu Thr Ser Thr S
#er Val Pro Ser Ala Lys
230
#235
#240
#245
AAG GCC AGA TGC TAT CCT GTC CCG AGA GTG G
#AG GAG GGA CCC CAC AGG 821
Lys Ala Arg Cys Tyr Pro Val Pro Arg Val G
#lu Glu Gly Pro His Arg
250
# 255
# 260
CAG GTG CTA CCA ACC CCA TCA GGC AAA TCA T
#GG GTG CCA AGT CCT GCT 869
Gln Val Leu Pro Thr Pro Ser Gly Lys Ser T
#rp Val Pro Ser Pro Ala
265
# 270
# 275
CGG TCC CCC GAG GTG CCT ACT GCA GAG AAA G
#AT TTG TCT TCT AAA GGA 917
Arg Ser Pro Glu Val Pro Thr Ala Glu Lys A
#sp Leu Ser Ser Lys Gly
280
# 285
# 290
AAG GTG TCT GAC CTG AGT CTC TCT GGG TCG G
#TG TGC TGT AAA CAC AAG 965
Lys Val Ser Asp Leu Ser Leu Ser Gly Ser V
#al Cys Cys Lys His Lys
295
# 300
# 305
CCC AGC TCC ACA TCT CTG CTG TCA CCA CCC C
#GC CAA AAT GCC TTT CAG 1013
Pro Ser Ser Thr Ser Leu Leu Ser Pro Pro A
#rg Gln Asn Ala Phe Gln
310
#315
#320
#325
CTC AGG CCA TTT ATT GAG ACC AGA CAT TTC C
#TT TAC TCC AGG GGA GAT 1061
Leu Arg Pro Phe Ile Glu Thr Arg His Phe L
#eu Tyr Ser Arg Gly Asp
330
# 335
# 340
GGC CAA GAG CGT CTA AAC CCC TCA TTC CTA C
#TC AGC AAC CTC CAG CCT 1109
Gly Gln Glu Arg Leu Asn Pro Ser Phe Leu L
#eu Ser Asn Leu Gln Pro
345
# 350
# 355
AAC TTG ACT GGG GCC AGG AGA CTG GTG GAG A
#TC ATC TTT CTG GGC TCA 1157
Asn Leu Thr Gly Ala Arg Arg Leu Val Glu I
#le Ile Phe Leu Gly Ser
360
# 365
# 370
AGG CCT AGG ACA TCA GGA CCA CTC TGC AGG A
#CA CAC CGT CTA TCG CGT 1205
Arg Pro Arg Thr Ser Gly Pro Leu Cys Arg T
#hr His Arg Leu Ser Arg
375
# 380
# 385
CGA TAC TGG CAG ATG CGG CCC CTG TTC CAA C
#AG CTG CTG GTG AAC CAT 1253
Arg Tyr Trp Gln Met Arg Pro Leu Phe Gln G
#ln Leu Leu Val Asn His
390
#395
#400
#405
GCA GAG TGC CAA TAT GTC AGA CTC CTC AGG T
#CA CAT TGC AGG TTT CGA 1301
Ala Glu Cys Gln Tyr Val Arg Leu Leu Arg S
#er His Cys Arg Phe Arg
410
# 415
# 420
ACA GCA AAC CAA CAG GTG ACA GAT GCC TTG A
#AC ACC AGC CCA CCG CAC 1349
Thr Ala Asn Gln Gln Val Thr Asp Ala Leu A
#sn Thr Ser Pro Pro His
425
# 430
# 435
CTC ATG GAT TTG CTC CGC CTG CAC AGC AGT C
#CC TGG CAG GTA TAT GGT 1397
Leu Met Asp Leu Leu Arg Leu His Ser Ser P
#ro Trp Gln Val Tyr Gly
440
# 445
# 450
TTT CTT CGG GCC TGT CTC TGC AAG GTG GTG T
#CT GCT AGT CTC TGG GGT 1445
Phe Leu Arg Ala Cys Leu Cys Lys Val Val S
#er Ala Ser Leu Trp Gly
455
# 460
# 465
ACC AGG CAC AAT GAG CGC CGC TTC TTT AAG A
#AC TTA AAG AAG TTC ATC 1493
Thr Arg His Asn Glu Arg Arg Phe Phe Lys A
#sn Leu Lys Lys Phe Ile
470
#475
#480
#485
TCG TTG GGG AAA TAC GGC AAG CTA TCA CTG C
#AG GAA CTG ATG TGG AAG 1541
Ser Leu Gly Lys Tyr Gly Lys Leu Ser Leu G
#ln Glu Leu Met Trp Lys
490
# 495
# 500
ATG AAA GTA GAG GAT TGC CAC TGG CTC CGC A
#GC AGC CCG GGG AAG GAC 1589
Met Lys Val Glu Asp Cys His Trp Leu Arg S
#er Ser Pro Gly Lys Asp
505
# 510
# 515
CGT GTC CCC GCT GCA GAG CAC CGT CTG AGG G
#AG AGG ATC CTG GCT ACG 1637
Arg Val Pro Ala Ala Glu His Arg Leu Arg G
#lu Arg Ile Leu Ala Thr
520
# 525
# 530
TTC CTG TTC TGG CTG ATG GAC ACA TAC GTG G
#TA CAG CTG CTT AGG TCA 1685
Phe Leu Phe Trp Leu Met Asp Thr Tyr Val V
#al Gln Leu Leu Arg Ser
535
# 540
# 545
TTC TTT TAC ATC ACA GAG AGC ACA TTC CAG A
#AG AAC AGG CTC TTC TTC 1733
Phe Phe Tyr Ile Thr Glu Ser Thr Phe Gln L
#ys Asn Arg Leu Phe Phe
550
#555
#560
#565
TAC CGT AAG AGT GTG TGG AGC AAG CTG CAG A
#GC ATT GGA GTC AGG CAA 1781
Tyr Arg Lys Ser Val Trp Ser Lys Leu Gln S
#er Ile Gly Val Arg Gln
570
# 575
# 580
CAC CTT GAG AGA GTG CGG CTA CGG GAG CTG T
#CA CAA GAG GAG GTC AGG 1829
His Leu Glu Arg Val Arg Leu Arg Glu Leu S
#er Gln Glu Glu Val Arg
585
# 590
# 595
CAT CAC CAG GAC ACC TGG CTA GCC ATG CCC A
#TC TGC AGA CTG CGC TTC 1877
His His Gln Asp Thr Trp Leu Ala Met Pro I
#le Cys Arg Leu Arg Phe
600
# 605
# 610
ATC CCC AAG CCC AAC GGC CTG CGG CCC ATT G
#TG AAC ATG AGT TAT AGC 1925
Ile Pro Lys Pro Asn Gly Leu Arg Pro Ile V
#al Asn Met Ser Tyr Ser
615
# 620
# 625
ATG GGT ACC AGA GCT TTG GGC AGA AGG AAG C
#AG GCC CAG CAT TTC ACC 1973
Met Gly Thr Arg Ala Leu Gly Arg Arg Lys G
#ln Ala Gln His Phe Thr
630
#635
#640
#645
CAG CGT CTC AAG ACT CTC TTC AGC ATG CTC A
#AC TAT GAG CGG ACA AAA 2021
Gln Arg Leu Lys Thr Leu Phe Ser Met Leu A
#sn Tyr Glu Arg Thr Lys
650
# 655
# 660
CAT CCT CAC CTT ATG GGG TCT TCT GTA CTG G
#GT ATG AAT GAC ATC TAC 2069
His Pro His Leu Met Gly Ser Ser Val Leu G
#ly Met Asn Asp Ile Tyr
665
# 670
# 675
AGG ACC TGG CGG GCC TTT GTG CTG CGT GTG C
#GT GCT CTG GAC CAG ACA 2117
Arg Thr Trp Arg Ala Phe Val Leu Arg Val A
#rg Ala Leu Asp Gln Thr
680
# 685
# 690
CCC AGG ATG TAC TTT GTT AAG GCA GAT GTG A
#CC GGG GCC TAT GAT GCC 2165
Pro Arg Met Tyr Phe Val Lys Ala Asp Val T
#hr Gly Ala Tyr Asp Ala
695
# 700
# 705
ATC CCC CAG GGT AAG CTG GTG GAG GTT GTT G
#CC AAT ATG ATC AGG CAC 2213
Ile Pro Gln Gly Lys Leu Val Glu Val Val A
#la Asn Met Ile Arg His
710
#715
#720
#725
TCG GAG AGC ACG TAC TGT ATC CGC CAG TAT G
#CA GTG GTC CGG AGA GAT 2261
Ser Glu Ser Thr Tyr Cys Ile Arg Gln Tyr A
#la Val Val Arg Arg Asp
730
# 735
# 740
AGC CAA GGC CAA GTC CAC AAG TCC TTT AGG A
#GA CAG GTC ACC ACC CTC 2309
Ser Gln Gly Gln Val His Lys Ser Phe Arg A
#rg Gln Val Thr Thr Leu
745
# 750
# 755
TCT GAC CTC CAG CCA TAC ATG GGC CAG TTC C
#TT AAG CAT CTG CAG GAT 2357
Ser Asp Leu Gln Pro Tyr Met Gly Gln Phe L
#eu Lys His Leu Gln Asp
760
# 765
# 770
TCA GAT GCC AGT GCA CTG AGG AAC TCC GTT G
#TC ATC GAG CAG AGC ATC 2405
Ser Asp Ala Ser Ala Leu Arg Asn Ser Val V
#al Ile Glu Gln Ser Ile
775
# 780
# 785
TCT ATG AAT GAG AGC AGC AGC AGC CTG TTT G
#AC TTC TTC CTG CAC TTC 2453
Ser Met Asn Glu Ser Ser Ser Ser Leu Phe A
#sp Phe Phe Leu His Phe
790
#795
#800
#805
CTG CGT CAC AGT GTC GTA AAG ATT GGT GAC A
#GG TGC TAT ACG CAG TGC 2501
Leu Arg His Ser Val Val Lys Ile Gly Asp A
#rg Cys Tyr Thr Gln Cys
810
# 815
# 820
CAG GGC ATC CCC CAG GGC TCC AGC CTA TCC A
#CC CTG CTC TGC AGT CTG 2549
Gln Gly Ile Pro Gln Gly Ser Ser Leu Ser T
#hr Leu Leu Cys Ser Leu
825
# 830
# 835
TGT TTC GGA GAC ATG GAG AAC AAG CTG TTT G
#CT GAG GTG CAG CGG GAT 2597
Cys Phe Gly Asp Met Glu Asn Lys Leu Phe A
#la Glu Val Gln Arg Asp
840
# 845
# 850
GGG TTG CTT TTA CGT TTT GTT GAT GAC TTT C
#TG TTG GTG ACG CCT CAC 2645
Gly Leu Leu Leu Arg Phe Val Asp Asp Phe L
#eu Leu Val Thr Pro His
855
# 860
# 865
TTG GAC CAA GCA AAA ACC TTC CTC AGC ACC C
#TG GTC CAT GGC GTT CCT 2693
Leu Asp Gln Ala Lys Thr Phe Leu Ser Thr L
#eu Val His Gly Val Pro
870
#875
#880
#885
GAG TAT GGG TGC ATG ATA AAC TTG CAG AAG A
#CA GTG GTG AAC TTC CCT 2741
Glu Tyr Gly Cys Met Ile Asn Leu Gln Lys T
#hr Val Val Asn Phe Pro
890
# 895
# 900
GTG GAG CCT GGT ACC CTG GGT GGT GCA GCT C
#CA TAC CAG CTG CCT GCT 2789
Val Glu Pro Gly Thr Leu Gly Gly Ala Ala P
#ro Tyr Gln Leu Pro Ala
905
# 910
# 915
CAC TGC CTG TTT CCC TGG TGT GGC TTG CTG C
#TG GAC ACT CAG ACT TTG 2837
His Cys Leu Phe Pro Trp Cys Gly Leu Leu L
#eu Asp Thr Gln Thr Leu
920
# 925
# 930
GAG GTG TTC TGT GAC TAC TCA GGT TAT GCC C
#AG ACC TCA ATT AAG ACG 2885
Glu Val Phe Cys Asp Tyr Ser Gly Tyr Ala G
#ln Thr Ser Ile Lys Thr
935
# 940
# 945
AGC CTC ACC TTC CAG AGT GTC TTC AAA GCT G
#GG AAG ACC ATG CGG AAC 2933
Ser Leu Thr Phe Gln Ser Val Phe Lys Ala G
#ly Lys Thr Met Arg Asn
950
#955
#960
#965
AAG CTC CTG TCG GTC TTG CGG TTG AAG TGT C
#AC GGT CTA TTT CTA GAC 2981
Lys Leu Leu Ser Val Leu Arg Leu Lys Cys H
#is Gly Leu Phe Leu Asp
970
# 975
# 980
TTG CAG GTG AAC AGC CTC CAG ACA GTC TGC A
#TC AAT ATA TAC AAG ATC 3029
Leu Gln Val Asn Ser Leu Gln Thr Val Cys I
#le Asn Ile Tyr Lys Ile
985
# 990
# 995
TTC CTG CTT CAG GCC TAC AGG TTC CAT GCA T
#GT GTG ATT CAG CTT CCC 3077
Phe Leu Leu Gln Ala Tyr Arg Phe His Ala C
#ys Val Ile Gln Leu Pro
1000
# 1005
# 1010
TTT GAC CAG CGT GTT AGG AAG AAC CTC ACA T
#TC TTT CTG GGC ATC ATC 3125
Phe Asp Gln Arg Val Arg Lys Asn Leu Thr P
#he Phe Leu Gly Ile Ile
1015
# 1020
# 1025
TCC AGC CAA GCA TCC TGC TGC TAT GCT ATC C
#TG AAG GTC AAG AAT CCA 3173
Ser Ser Gln Ala Ser Cys Cys Tyr Ala Ile L
#eu Lys Val Lys Asn Pro
1030 103
#5 1040
# 1045
GGA ATG ACA CTA AAG GCC TCT GGC TCC TTT C
#CT CCT GAA GCC GCA CAT 3221
Gly Met Thr Leu Lys Ala Ser Gly Ser Phe P
#ro Pro Glu Ala Ala His
1050
# 1055
# 1060
TGG CTC TGC TAC CAG GCC TTC CTG CTC AAG C
#TG GCT GCT CAT TCT GTC 3269
Trp Leu Cys Tyr Gln Ala Phe Leu Leu Lys L
#eu Ala Ala His Ser Val
1065
# 1070
# 1075
ATC TAC AAA TGT CTC CTG GGA CCT CTG AGG A
#CA GCC CAA AAA CTG CTG 3317
Ile Tyr Lys Cys Leu Leu Gly Pro Leu Arg T
#hr Ala Gln Lys Leu Leu
1080
# 1085
# 1090
TGC CGG AAG CTC CCA GAG GCG ACA ATG ACC A
#TC CTT AAA GCT GCA GCT 3365
Cys Arg Lys Leu Pro Glu Ala Thr Met Thr I
#le Leu Lys Ala Ala Ala
1095
# 1100
# 1105
GAC CCA GCC CTA AGC ACA GAC TTT CAG ACC A
#TT TTG GAC TAACCCTGTC 3414
Asp Pro Ala Leu Ser Thr Asp Phe Gln Thr I
#le Leu Asp
1110 111
#5 1120
TCCTTCCGCT AGATGAACAT GAAGGGCGAA TTCCAGCACA CTGGCGGCCG T
#TACTAGTGG 3474
ATCCGAGCTC GGTACCAAGC TT
#
# 3496
(2) INFORMATION FOR SEQ ID NO:2:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 1122 amino
# acids
(B) TYPE: amino acid
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: protein
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:
Met Thr Arg Ala Pro Arg Cys Pro Ala Val A
#rg Ser Leu Leu Arg Ser
1 5
# 10
# 15
Arg Tyr Arg Glu Val Trp Pro Leu Ala Thr P
#he Val Arg Arg Leu Gly
20
# 25
# 30
Pro Glu Gly Arg Arg Leu Val Gln Pro Gly A
#sp Pro Lys Ile Tyr Arg
35
# 40
# 45
Thr Leu Val Ala Gln Cys Leu Val Cys Met H
#is Trp Gly Ser Gln Pro
50
# 55
# 60
Pro Pro Ala Asp Leu Ser Phe His Gln Val S
#er Ser Leu Lys Glu Leu
65
# 70
# 75
# 80
Val Ala Arg Val Val Gln Arg Leu Cys Glu A
#rg Asn Glu Arg Asn Val
85
# 90
# 95
Leu Ala Phe Gly Phe Glu Leu Leu Asn Glu A
#la Arg Gly Gly Pro Pro
100
# 105
# 110
Met Ala Phe Thr Ser Ser Val Arg Ser Tyr L
#eu Pro Asn Thr Val Ile
115
# 120
# 125
Glu Thr Leu Arg Val Ser Gly Ala Trp Met L
#eu Leu Leu Ser Arg Val
130
# 135
# 140
Gly Asp Asp Leu Leu Val Tyr Leu Leu Ala H
#is Cys Ala Leu Tyr Leu
145
#150
#155
#160
Leu Val Pro Pro Ser Cys Ala Tyr Gln Val C
#ys Gly Ser Pro Leu Tyr
165
# 170
# 175
Gln Ile Cys Ala Thr Thr Asp Ile Trp Pro S
#er Val Ser Ala Ser Tyr
180
# 185
# 190
Arg Pro Thr Arg Pro Val Gly Arg Asn Phe T
#hr Asn Leu Arg Phe Leu
195
# 200
# 205
Gln Gln Ile Lys Ser Ser Ser Arg Gln Glu A
#la Pro Lys Pro Leu Ala
210
# 215
# 220
Leu Pro Ser Arg Gly Thr Lys Arg His Leu S
#er Leu Thr Ser Thr Ser
225
#230
#235
#240
Val Pro Ser Ala Lys Lys Ala Arg Cys Tyr P
#ro Val Pro Arg Val Glu
245
# 250
# 255
Glu Gly Pro His Arg Gln Val Leu Pro Thr P
#ro Ser Gly Lys Ser Trp
260
# 265
# 270
Val Pro Ser Pro Ala Arg Ser Pro Glu Val P
#ro Thr Ala Glu Lys Asp
275
# 280
# 285
Leu Ser Ser Lys Gly Lys Val Ser Asp Leu S
#er Leu Ser Gly Ser Val
290
# 295
# 300
Cys Cys Lys His Lys Pro Ser Ser Thr Ser L
#eu Leu Ser Pro Pro Arg
305
#310
#315
#320
Gln Asn Ala Phe Gln Leu Arg Pro Phe Ile G
#lu Thr Arg His Phe Leu
325
# 330
# 335
Tyr Ser Arg Gly Asp Gly Gln Glu Arg Leu A
#sn Pro Ser Phe Leu Leu
340
# 345
# 350
Ser Asn Leu Gln Pro Asn Leu Thr Gly Ala A
#rg Arg Leu Val Glu Ile
355
# 360
# 365
Ile Phe Leu Gly Ser Arg Pro Arg Thr Ser G
#ly Pro Leu Cys Arg Thr
370
# 375
# 380
HisArg Leu Ser Arg Arg Tyr Trp Gln Met A
#rg Pro Leu Phe Gln Gln
385
#390
#395
#400
Leu Leu Val Asn His Ala Glu Cys Gln Tyr V
#al Arg Leu Leu Arg Ser
405
# 410
# 415
His Cys Arg Phe Arg Thr Ala Asn Gln Gln V
#al Thr Asp Ala Leu Asn
420
# 425
# 430
Thr Ser Pro Pro His Leu Met Asp Leu Leu A
#rg Leu His Ser Ser Pro
435
# 440
# 445
Trp Gln Val Tyr Gly Phe Leu Arg Ala Cys L
#eu Cys Lys Val Val Ser
450
# 455
# 460
Ala Ser Leu Trp Gly Thr Arg His Asn Glu A
#rg Arg Phe Phe Lys Asn
465
#470
#475
#480
Leu Lys Lys Phe Ile Ser Leu Gly Lys Tyr G
#ly Lys Leu Ser Leu Gln
485
# 490
# 495
Glu Leu Met Trp Lys Met Lys Val Glu Asp C
#ys His Trp Leu Arg Ser
500
# 505
# 510
Ser Pro Gly Lys Asp Arg Val Pro Ala Ala G
#lu His Arg Leu Arg Glu
515
# 520
# 525
Arg Ile Leu Ala Thr Phe Leu Phe Trp Leu M
#et Asp Thr Tyr Val Val
530
# 535
# 540
Gln Leu Leu Arg Ser Phe Phe Tyr Ile Thr G
#lu Ser Thr Phe Gln Lys
545
#550
#555
#560
Asn Arg Leu Phe Phe Tyr Arg Lys Ser Val T
#rp Ser Lys Leu Gln Ser
565
# 570
# 575
Ile Gly Val Arg Gln His Leu Glu Arg Val A
#rg Leu Arg Glu Leu Ser
580
# 585
# 590
Gln Glu Glu Val Arg His His Gln Asp Thr T
#rp Leu Ala Met Pro Ile
595
# 600
# 605
Cys Arg Leu Arg Phe Ile Pro Lys Pro Asn G
#ly Leu Arg Pro Ile Val
610
# 615
# 620
Asn Met Ser Tyr Ser Met Gly Thr Arg Ala L
#eu Gly Arg Arg Lys Gln
625
#630
#635
#640
Ala Gln His Phe Thr Gln Arg Leu Lys Thr L
#eu Phe Ser Met Leu Asn
645
# 650
# 655
Tyr Glu Arg Thr Lys His Pro His Leu Met G
#ly Ser Ser Val Leu Gly
660
# 665
# 670
Met Asn Asp Ile Tyr Arg Thr Trp Arg Ala P
#he Val Leu Arg Val Arg
675
# 680
# 685
Ala Leu Asp Gln Thr Pro Arg Met Tyr Phe V
#al Lys Ala Asp Val Thr
690
# 695
# 700
Gly Ala Tyr Asp Ala Ile Pro Gln Gly Lys L
#eu Val Glu Val Val Ala
705
#710
#715
#720
Asn Met Ile Arg His Ser Glu Ser Thr Tyr C
#ys Ile Arg Gln Tyr Ala
725
# 730
# 735
Val Val Arg Arg Asp Ser Gln Gly Gln Val H
#is Lys Ser Phe Arg Arg
740
# 745
# 750
Gln Val Thr Thr Leu Ser Asp Leu Gln Pro T
#yr Met Gly Gln Phe Leu
755
# 760
# 765
Lys His Leu Gln Asp Ser Asp Ala Ser Ala L
#eu Arg Asn Ser Val Val
770
# 775
# 780
Ile Glu Gln Ser Ile Ser Met Asn Glu Ser S
#er Ser Ser Leu Phe Asp
785
#790
#795
#800
Phe Phe Leu His Phe Leu Arg His Ser Val V
#al Lys Ile Gly Asp Arg
805
# 810
# 815
Cys Tyr Thr Gln Cys Gln Gly Ile Pro Gln G
#ly Ser Ser Leu Ser Thr
820
# 825
# 830
Leu Leu Cys Ser Leu Cys Phe Gly Asp Met G
#lu Asn Lys Leu Phe Ala
835
# 840
# 845
Glu Val Gln Arg Asp Gly Leu Leu Leu Arg P
#he Val Asp Asp Phe Leu
850
# 855
# 860
Leu Val Thr Pro His Leu Asp Gln Ala Lys T
#hr Phe Leu Ser Thr Leu
865
#870
#875
#880
Val His Gly Val Pro Glu Tyr Gly Cys Met I
#le Asn Leu Gln Lys Thr
885
# 890
# 895
Val Val Asn Phe Pro Val Glu Pro Gly Thr L
#eu Gly Gly Ala Ala Pro
900
# 905
# 910
Tyr Gln Leu Pro Ala His Cys Leu Phe Pro T
#rp Cys Gly Leu Leu Leu
915
# 920
# 925
Asp Thr Gln Thr Leu Glu Val Phe Cys Asp T
#yr Ser Gly Tyr Ala Gln
930
# 935
# 940
Thr Ser Ile Lys Thr Ser Leu Thr Phe Gln S
#er Val Phe Lys Ala Gly
945
#950
#955
#960
Lys Thr Met Arg Asn Lys Leu Leu Ser Val L
#eu Arg Leu Lys Cys His
965
# 970
# 975
Gly Leu Phe Leu Asp Leu Gln Val Asn Ser L
#eu Gln Thr Val Cys Ile
980
# 985
# 990
Asn Ile Tyr Lys Ile Phe Leu Leu Gln Ala T
#yr Arg Phe His Ala Cys
995
# 1000
# 1005
Val Ile Gln Leu Pro Phe Asp Gln Arg Val A
#rg Lys Asn Leu Thr Phe
1010
# 1015
# 1020
Phe Leu Gly Ile Ile Ser Ser Gln Ala Ser C
#ys Cys Tyr Ala Ile Leu
1025 103
#0 1035
# 1040
Lys Val Lys Asn Pro Gly Met Thr Leu Lys A
#la Ser Gly Ser Phe Pro
1045
# 1050
# 1055
Pro Glu Ala Ala His Trp Leu Cys Tyr Gln A
#la Phe Leu Leu Lys Leu
1060
# 1065
# 1070
Ala Ala His Ser Val Ile Tyr Lys Cys Leu L
#eu Gly Pro Leu Arg Thr
1075
# 1080
# 1085
Ala Gln Lys Leu Leu Cys Arg Lys Leu Pro G
#lu Ala Thr Met Thr Ile
1090
# 1095
# 1100
Leu Lys Ala Ala Ala Asp Pro Ala Leu Ser T
#hr Asp Phe Gln Thr Ile
1105 111
#0 1115
# 1120
Leu Asp
(2) INFORMATION FOR SEQ ID NO:3:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 1132 amino
# acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: protein
(ix) FEATURE:
(A) NAME/KEY: Protein
(B) LOCATION: 1..1132
(D) OTHER INFORMATION:
#/note= "human telomerase reverse
transcripta
#se (hTRT)"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:
Met Pro Arg Ala Pro Arg Cys Arg Ala Val A
#rg Ser Leu Leu Arg Ser
1 5
# 10
# 15
His Tyr Arg Glu Val Leu Pro Leu Ala Thr P
#he Val Arg Arg Leu Gly
20
# 25
# 30
Pro Gln Gly Trp Arg Leu Val Gln Arg Gly A
#sp Pro Ala Ala Phe Arg
35
# 40
# 45
Ala Leu Val Ala Gln Cys Leu Val Cys Val P
#ro Trp Asp Ala Arg Pro
50
# 55
# 60
Pro Pro Ala Ala Pro Ser Phe Arg Gln Val S
#er Cys Leu Lys Glu Leu
65
#70
#75
#80
Val Ala Arg Val Leu Gln Arg Leu Cys Glu A
#rg Gly Ala Lys Asn Val
85
# 90
# 95
Leu Ala Phe Gly Phe Ala Leu Leu Asp Gly A
#la Arg Gly Gly Pro Pro
100
# 105
# 110
Glu Ala Phe Thr Thr Ser Val Arg Ser Tyr L
#eu Pro Asn Thr Val Thr
115
# 120
# 125
Asp Ala Leu Arg Gly Ser Gly Ala Trp Gly L
#eu Leu Leu Arg Arg Val
130
# 135
# 140
Gly Asp Asp Val Leu Val His Leu Leu Ala A
#rg Cys Ala Leu Phe Val
145
#150
#155
#160
Leu Val Ala Pro Ser Cys Ala Tyr Gln Val C
#ys Gly Pro Pro Leu Tyr
165
# 170
# 175
Gln Leu Gly Ala Ala Thr Gln Ala Arg Pro P
#ro Pro His Ala Ser Gly
180
# 185
# 190
Pro Arg Arg Arg Leu Gly Cys Glu Arg Ala T
#rp Asn His Ser Val Arg
195
# 200
# 205
Glu Ala Gly Val Pro Leu Gly Leu Pro Ala P
#ro Gly Ala Arg Arg Arg
210
# 215
# 220
Gly Gly Ser Ala Ser Arg Ser Leu Pro Leu P
#ro Lys Arg Pro Arg Arg
225
#230
#235
#240
Gly Ala Ala Pro Glu Pro Glu Arg Thr Pro V
#al Gly Gln Gly Ser Trp
245
# 250
# 255
Ala His Pro Gly Arg Thr Arg Gly Pro Ser A
#sp Arg Gly Phe Cys Val
260
# 265
# 270
Val Ser Pro Ala Arg Pro Ala Glu Glu Ala T
#hr Ser Leu Glu Gly Ala
275
# 280
# 285
Leu Ser Gly Thr Arg His Ser His Pro Ser V
#al Gly Arg Gln His His
290
# 295
# 300
Ala Gly Pro Pro Ser Thr Ser Arg Pro Pro A
#rg Pro Trp Asp Thr Pro
305
#310
#315
#320
Cys Pro Pro Val Tyr Ala Glu Thr Lys His P
#he Leu Tyr Ser Ser Gly
325
# 330
# 335
Asp Lys Glu Gln Leu Arg Pro Ser Phe Leu L
#eu Ser Ser Leu Arg Pro
340
# 345
# 350
Ser Leu Thr Gly Ala Arg Arg Leu Val Glu T
#hr Ile Phe Leu Gly Ser
355
# 360
# 365
Arg Pro Trp Met Pro Gly Thr Pro Arg Arg L
#eu Pro Arg Leu Pro Gln
370
# 375
# 380
Arg Tyr Trp Gln Met Arg Pro Leu Phe Leu G
#lu Leu Leu Gly Asn His
385
#390
#395
#400
Ala Gln Cys Pro Tyr Gly Val Leu Leu Lys T
#hr His Cys Pro Leu Arg
405
# 410
# 415
Ala Ala Val Thr Pro Ala Ala Gly Val Cys A
#la Arg Glu Lys Pro Gln
420
# 425
# 430
Gly Ser Val Ala Ala Pro Glu Glu Glu Asp T
#hr Asp Pro Arg Arg Leu
435
# 440
# 445
Val Gln Leu Leu Arg Gln His Ser Ser Pro T
#rp Gln Val Tyr Gly Phe
450
# 455
# 460
Val Arg Ala Cys Leu Arg Arg Leu Val Pro P
#ro Gly Leu Trp Gly Ser
465
#470
#475
#480
Arg His Asn Glu Arg Arg Phe Leu Arg Asn T
#hr Lys Lys Phe Ile Ser
485
# 490
# 495
Leu Gly Lys His Ala Lys Leu Ser Leu Gln G
#lu Leu Thr Trp Lys Met
500
# 505
# 510
Ser Val Arg Asp Cys Ala Trp Leu Arg Arg S
#er Pro Gly Val Gly Cys
515
# 520
# 525
Val Pro Ala Ala Glu His Arg Leu Arg Glu G
#lu Ile Leu Ala Lys Phe
530
# 535
# 540
Leu His Trp Leu Met Ser Val Tyr Val Val G
#lu Leu Leu Arg Ser Phe
545
#550
#555
#560
Phe Tyr Val Thr Glu Thr Thr Phe Gln Lys A
#sn Arg Leu Phe Phe Tyr
565
# 570
# 575
Arg Lys Ser Val Trp Ser Lys Leu Gln Ser I
#le Gly Ile Arg Gln His
580
# 585
# 590
Leu Lys Arg Val Gln Leu Arg Glu Leu Ser G
#lu Ala Glu Val Arg Gln
595
# 600
# 605
His Arg Glu Ala Arg Pro Ala Leu Leu Thr S
#er Arg Leu Arg Phe Ile
610
# 615
# 620
Pro Lys Pro Asp Gly Leu Arg Pro Ile Val A
#sn Met Asp Tyr Val Val
625
#630
#635
#640
Gly Ala Arg Thr Phe Arg Arg Glu Lys Arg A
#la Glu Arg Leu Thr Ser
645
# 650
# 655
Arg Val Lys Ala Leu Phe Ser Val Leu Asn T
#yr Glu Arg Ala Arg Arg
660
# 665
# 670
Pro Gly Leu Leu Gly Ala Ser Val Leu Gly L
#eu Asp Asp Ile His Arg
675
# 680
# 685
Ala Trp Arg Thr Phe Val Leu Arg Val Arg A
#la Gln Asp Pro Pro Pro
690
# 695
# 700
Glu Leu Tyr Phe Val Lys Val Asp Val Thr G
#ly Ala Tyr Asp Thr Ile
705
#710
#715
#720
Pro Gln Asp Arg Leu Thr Glu Val Ile Ala S
#er Ile Ile Lys Pro Gln
725
# 730
# 735
Asn Thr Tyr Cys Val Arg Arg Tyr Ala Val V
#al Gln Lys Ala Ala His
740
# 745
# 750
Gly His Val Arg Lys Ala Phe Lys Ser His V
#al Ser Thr Leu Thr Asp
755
# 760
# 765
Leu Gln Pro Tyr Met Arg Gln Phe Val Ala H
#is Leu Gln Glu Thr Ser
770
# 775
# 780
Pro Leu Arg Asp Ala Val Val Ile Glu Gln S
#er Ser Ser Leu Asn Glu
785
#790
#795
#800
Ala Ser Ser Gly Leu Phe Asp Val Phe Leu A
#rg Phe Met Cys His His
805
# 810
# 815
Ala Val Arg Ile Arg Gly Lys Ser Tyr Val G
#ln Cys Gln Gly Ile Pro
820
# 825
# 830
Gln Gly Ser Ile Leu Ser Thr Leu Leu Cys S
#er Leu Cys Tyr Gly Asp
835
# 840
# 845
Met Glu Asn Lys Leu Phe Ala Gly Ile Arg A
#rg Asp Gly Leu Leu Leu
850
# 855
# 860
Arg Leu Val Asp Asp Phe Leu Leu Val Thr P
#ro His Leu Thr His Ala
865
#870
#875
#880
Lys Thr Phe Leu Arg Thr Leu Val Arg Gly V
#al Pro Glu Tyr Gly Cys
885
# 890
# 895
Val Val Asn Leu Arg Lys Thr Val Val Asn P
#he Pro Val Glu Asp Glu
900
# 905
# 910
Ala Leu Gly Gly Thr Ala Phe Val Gln Met P
#ro Ala His Gly Leu Phe
915
# 920
# 925
Pro Trp Cys Gly Leu Leu Leu Asp Thr Arg T
#hr Leu Glu Val Gln Ser
930
# 935
# 940
Asp Tyr Ser Ser Tyr Ala Arg Thr Ser Ile A
#rg Ala Ser Leu Thr Phe
945
#950
#955
#960
Asn Arg Gly Phe Lys Ala Gly Arg Asn Met A
#rg Arg Lys Leu Phe Gly
965
# 970
# 975
Val Leu Arg Leu Lys Cys His Ser Leu Phe L
#eu Asp Leu Gln Val Asn
980
# 985
# 990
Ser Leu Gln Thr Val Cys Thr Asn Ile Tyr L
#ys Ile Leu Leu Leu Gln
995
# 1000
# 1005
Ala Tyr Arg Phe His Ala Cys Val Leu Gln L
#eu Pro Phe His Gln Gln
1010
# 1015
# 1020
Val Trp Lys Asn Pro Thr Phe Phe Leu Arg V
#al Ile Ser Asp Thr Ala
1025 103
#0 1035
# 1040
Ser Leu Cys Tyr Ser Ile Leu Lys Ala Lys A
#sn Ala Gly Met Ser Leu
1045
# 1050
# 1055
Gly Ala Lys Gly Ala Ala Gly Pro Leu Pro S
#er Glu Ala Val Gln Trp
1060
# 1065
# 1070
Leu Cys His Gln Ala Phe Leu Leu Lys Leu T
#hr Arg His Arg Val Thr
1075
# 1080
# 1085
Tyr Val Pro Leu Leu Gly Ser Leu Arg Thr A
#la Gln Thr Gln Leu Ser
1090
# 1095
# 1100
Arg Lys Leu Pro Gly Thr Thr Leu Thr Ala L
#eu Glu Ala Ala Ala Asn
1105 111
#0 1115
# 1120
Pro Ala Leu Pro Ser Asp Phe Lys Thr Ile L
#eu Asp
1125
# 1130
(2) INFORMATION FOR SEQ ID NO:4:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 1808 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..1808
(D) OTHER INFORMATION:
#/note= "preliminary sequence of genomic
mouse te
#lomerase reverse transcriptase
(mTRT) p
#romoter region"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 1680
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) cDNA start site"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 1709
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) ORF start site"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:
AAAGCAGGCC TGTAACACAA AGGTCCTTTT TCCTGGTTTA TCGTGGCTGG T
#AGACAATTT 60
CCACTTGTTT TCCACTTCAG TTTTTTCTAC TCGGTTGTTA TTGGATTCTG A
#TGCTTGAAC 120
CCAGGTTGGT AGTCAGCAAG TGCACCCCTT CCTTCTTTTT CTTGGTTTTT T
#TGAGGCAGG 180
TCTCATTTTG CCCAAGTGGA CCTAAATTTC AGCATGTAGT GGCTGGTTTN G
#AATGCTTTT 240
TCATCCTGCT NTACTTCCCA AGAGTAGCTA ACAAGTGTGC ACCACCATGC C
#CCGCGATAT 300
TTTTATTTTT GAGACTGTTT TCTATGCTGG TTTCTTTGGG GAACTACACT A
#AGGTAGCTT 360
ACAAGTGTGC ACCACCATGC CCCGCGATAT TCTTATTTTT GAGACTGTTT T
#CTATGCTGG 420
TTTCTTTGGG GAACTACACT AAGGTAGCTT CATTGTTGGC ATAAATTTCT C
#AGTTCAGGC 480
CCATATCTCT TAAGTAGCAG AACTAAGCCA AATCTTCAAA CAAACCCCTT C
#AAAAAGACT 540
GATGTCCACT AAACGGACTT CTAAAATAGC TCCCTGTAAT CCTGAGCATT T
#ACCAAGGCG 600
GCAGACTTCC TATAAGGGAG TAAATATGAA AACGCGCCTG TTCAAATGCT A
#GGTCGGTGG 660
ATAGAAGCAA TTTCCTCAGA AAGCTGAAGG CACCAAAGGT TATATTTGTT A
#GCATTTCAG 720
TGTTTGCCAA ACTCAGCTAC AGTAGAGATC ACAGATTCCC TATTTCCCAG A
#GATTCAAAA 780
TTCAGCAGCC CCTCTCTAAC TATGGCTCAG AGTCGTGTCA TTACATATGC C
#CCAACAACA 840
ACCCCCACCC CTATCCTACC CCCGCCTCAC ACGTGCAAGT ACTATCACAG T
#TGCCAACCT 900
AGCAGAGCTG CCATCCTAAG GTCGAGGTCG CCGCTTTGGC TGTGTGCACA G
#GCAAGCGCC 960
CTCACCCAAT GGCCCTGGCC TTGCTATGGG TGCGTGAGTT GAGATGATGC T
#CTGGACTCT 1020
GAGGTGAAGG CCACTGGAAC AGTGAAAAAA GCTAACGCAG GGCTTTTACC T
#AGGTCCCCT 1080
TCCTTTGGTG GTGGGTGTTT ACGGAACATA TTTGGGATCT GGAGTGTATG G
#TCGCACCAC 1140
AATAAAGCCT TAACCTATAT AGTAGAATGT TCAGCTGTAA TCATTAAGAA C
#TGAGATTGC 1200
CACCACCCAC CTCACTGTCT GTGTCAACCA CAGCAGGCTG GAGCAGTCAG C
#TCAGGAACA 1260
GGCAAAACCT TAGGTCCTCC GCCTACCTAA CCTTCAATAC ATCAAGGATA G
#GCTTCTTTG 1320
CTTGCCCAAA CCTCGCCCCA GTCTAGACCA CCTGGGGATT CCCAGCTCAG G
#GCGAAAAGG 1380
AAGCCCGAGA AGCATTCTGT AGAGGGAAAT CCTGCATGAG TGCGCCCCCT T
#TCGTTACTC 1440
CAACACATCC AGCAACCACT GAACTTGGCC GGGGAACACA CCTGGTCCTC A
#TGCACCAGC 1500
ATTGTGACCA TCAACGGAAA AGTACTATTG CTGCGACCCC GCCCCTTCCG C
#TACAACGCT 1560
TGGTCCGCCT GAATCCCGCC CCTTCCTCCG TTCCCAGCCT CATCTTTTTC G
#TCGTGGACT 1620
CTCAGTGGCC TGGGTCCTGG CTGTTTTCTA AGCACACCCT TGCATCTTGG T
#TCCCGCACG 1680
TGGGAGGCCC ATCCCGGCCT TGAGCACAAT GACCCGCGCT CCTCGTTGCC C
#CGCGGTGCG 1740
CTCTCTGCTG CGCAGCCGAT ACCGGGAGGT GTGGCCGCTG GCAACCTTTG T
#GCGGCGCCT 1800
GGGGCCCG
#
#
# 1808
(2) INFORMATION FOR SEQ ID NO:5:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 2651 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..2651
(D) OTHER INFORMATION:
#/note= "preliminary sequence of B2.18
containing
#the genomic promoter region
of mouse
# telomerase reverse
transcripta
#se (mTRT)"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 2057
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) cDNA start site"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 2087
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) ORF start site"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:
AAACAAAGTC AATGAGGAAT GGCTGTGTTC CATCTTGACC ACTGAGAAGT A
#AAACCGGGT 60
GCAGTGATGT CCAAAAAGGC AAGGTGACAG CAGAGCGGAG GCCCCAATCT A
#GAGCAGGGC 120
CTTCGGTTTG AATGGGGGAG ATCAAACGGG AGTTGGTTTC TGCCAGCACG T
#TGGGGTAGA 180
AGGTGGAACA TGAAAGGTCC CCGAGGATTT CGAGAGTCCA TAGGGGTAGC G
#ACACCCGAG 240
GTCTTCTTTT TCACCTCCTT CCCTGCAGGG GAGATGACTT TTACCACAGT C
#GTTTATGGG 300
AAAGTTCCTA GGGGCAGCCC CTCCCCAAAA AGGCTCTCCC TGGCCTCATG T
#TTCAAAGCA 360
CAGCTTTTTA AAGCAGGCCT GTTAAGCACA AAGGATCCCG AATCCTGGCT T
#CATCGTTGG 420
CTGGTAGACA ACTTCCACTC GTTTTCCACT TCAGTTTCTT CTAACTCTGT T
#GTTATTTGA 480
TTCTGATGCT TGAACCCAGG GTTGTGTAGT CAGCAAGTGC TACCCCCTCC T
#CCTCTTCTT 540
TGTTTTTTTG AGGCAGGGTC TCATTTTGCC CAAGTGGACC TAAATTTCAG C
#ATGTAGCTG 600
GCCTGGTTTT GAATGCCTTC TCATCCTGCC TCTACTTCCC AAGAGTAGCT T
#ACAAGTGTG 660
CACCACCATG CCCCGCGATA TTCTTATTTT TGAGACTGTT TTCTATGCTG G
#TTTCTTTGG 720
GGAACTACAC TAAGGTAGCT TACAAGTGTG CACCACCATG CCCCGCGATA T
#TCTTATTTT 780
TGAGACTGTT TTCTATGCTG GTTTCTTTGG GGAACTACAC TAAGGTAGCT T
#CATTGTTGG 840
CATAAATTTC TCAGTTCAGG CCCATATCTC CTAAGTAGCA GAACTAAGCA A
#ATCTCAAAC 900
AAACCCCTCA AAAAGACTGA TGTCCACTAA ACGGACTTCT AAAATAGCTC C
#CTGTAATCC 960
TGAGCATTTA CAAGGCGGCA GACCTCCTAT AAGGGAGTAA ATATGAAAAC G
#CGCCTGTTC 1020
AAATGCTAGG TCGGTGGATA GAAGCAATTT CCTCAGAAAG CTGAAGGCAC C
#AAAGGTTAT 1080
ATTTGTTAGC ATTTCAGTGT TTGCCAAACT CAGCTACAGT AGAGATCACA G
#ATTCCCTAT 1140
TTCCCAGAGA TTCAAAATTC AGCAGCCCCT CTCTAACTAT GGCTCAGAGT C
#GTGTCATTA 1200
CATATGCCCC AACAACAACC CCCACCCCTA TCCTACCCCC GCCTCACACG T
#GCAAGTACT 1260
ATCACAGTTG CCAACCTAGC AGAGCTGCCA TCCTAAGGTC GAGGTCGCCG C
#TTTGGCTGT 1320
GTGCACAGGC AAGCGCCCTC ACCCAATGGC CCTGGCCTTG CTATGGGTGC G
#TGAGTTGAG 1380
ATGATGCTCT GGACTCTGAG GTGAAGGCCA CTGGAACAGT GAAAAAAGCT A
#ACGCAGGGC 1440
TTTTACCTAG GTCCCCTTCC TTTGGTGGTG GGTGTTTACG GAACATATTT G
#GGATCTGGA 1500
GTGTATGGTC GCACCACAAT AAAGCCTTAA CCTATATAGT AGAATTTCAG C
#TGTAATCAT 1560
TAAGAACTGA GATTGCCACC ACCCACCTCA CTGTCTGTGT CAACCACAGC A
#GGCTGGAGC 1620
AGTCAGCTCA GGAACAGGCA AAACCTTAGG TCCCTCCGCC TACCTAACCT T
#CAATACATC 1680
AAGGATAGGC TTCTTTGCTT GCCCAAACCT CGCCCCAGTC TAGACCACCT G
#GGGATTCCC 1740
AGCTCAGGGC GAAAAGGAAG CCCGAGAAGC ATTCTGTAGA GGGAAATCCT G
#CATGAGTGC 1800
GCCCCCTTTC GTTACTCCAA CACATCCAGC AACCACTGAA CTTGGCCGGG G
#AACACACCT 1860
GGTCCTCATG CACCAGCATT GTGACCATCA ACGGAAAAGT ACTATTGCTG C
#GACCCCGCC 1920
CCTTCCGCTA CAACGCTTGG TCCGCCTGAA TCCCGCCCCT TCCTCCGTTC C
#CAGCCTCAT 1980
CTTTTTCGTC GTGGACTCTC AGTGGCCTGG GTCCTGGCTG TTTTCTAAGC A
#CACCCTTGC 2040
ATCTTGGTTC CCGCACGTGG GAAGGCCCAT CCCGGCCTTG AGCACAATGA C
#CCGCGCTCC 2100
TCGTTGCCCC GCGGTGCGCT CTCTGCTGCG CAGCCGATAC CGGGAGGTGT G
#GCCGCTGGC 2160
AACCTTTGTG CGGCGCCTGG GGCCCGAGGG CAGGCGGCTT GTGCAACCCG G
#GGACCGAAG 2220
ATCTACCGCA CTTTGGGTTG CCCAATGCCT AGTGTGCATG CACTGGGGCT C
#ACAGCCTCC 2280
ACCTGCCGAC CTTTCCTTCC ACCAGGTGGG CCTCCAGGCG GGATCCCCAT G
#GGTCAGGGG 2340
CGGAAAGCCG GGAGGACGTG GGATAGTGCG TCTAGCTCAT GTGTCAAGAC C
#CTCTTCTCC 2400
TTACCAGGTG TCATCCCTGA AAAGAGCTGG TGGCCAGGGT TGTGCAGAGA C
#TCTGCGAGC 2460
GCAACGAGAG AAACGTGCTG GCTTTTGGCT TTGAGCTGCT TAACGAAGCC A
#GAAGCGGGC 2520
CTCCCATGGC CTTCACTAAT TAGCGTGCGT AAGCTACTTG CCCAACACTG T
#TATTGAAAA 2580
CCTGCGTGTC AGTGGTGCAT GGATGCTACT GTTGAGCCGA ATGGGCGACA C
#CTGCTGGTC 2640
TACCTGCTGG C
#
#
# 2651
(2) INFORMATION FOR SEQ ID NO:6:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 18 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..18
(D) OTHER INFORMATION:
#/note= "human telomerase reverse
transcripta
#se (hTRT) substrate oligonucleotide "TS""
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:
AATCCGTCGA GCAGAGTT
#
#
# 18
(2) INFORMATION FOR SEQ ID NO:7:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 6 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..6
(D) OTHER INFORMATION:
#/note= "human telomeric repeat"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:
TTAGGG
#
#
# 6
(2) INFORMATION FOR SEQ ID NO:8:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "3' primer hTRT.28"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:
CTCGGACCAG GGTCCTGAGG AA
#
# 22
(2) INFORMATION FOR SEQ ID NO:9:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 23 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..23
(D) OTHER INFORMATION:
#/note= "primer mTRT.35"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:
CTTCCTCAGG ACCCTGGTCC GAG
#
# 23
(2) INFORMATION FOR SEQ ID NO:10:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "primer mTRT.27"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:
ATTGAGGTCT GGGCATACCT GC
#
# 22
(2) INFORMATION FOR SEQ ID NO:11:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "3' primer encoding
carboxy-ter
#minus of hTRT"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:
TCAGCGTCGT CCCCGGGAGC TT
#
# 22
(2) INFORMATION FOR SEQ ID NO:12:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "5' primer from upstream
mTRT Ra-
#200"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:
TCACCCTCTG AGGCTTCGGT GT
#
# 22
(2) INFORMATION FOR SEQ ID NO:13:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 21 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..21
(D) OTHER INFORMATION:
#/note= "primer mTRT.10"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:
CGTCGATACT GGCAGATGCG G
#
#
#21
(2) INFORMATION FOR SEQ ID NO:14:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 24 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..24
(D) OTHER INFORMATION:
#/note= "primer mTRT.53"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:
GTGCTGAGGC TACAATGCCC ATGT
#
# 24
(2) INFORMATION FOR SEQ ID NO:15:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 21 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..21
(D) OTHER INFORMATION:
#/note= "5' primer mTRT.9"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:
CTTTTACATC ACAGAGAGCA C
#
#
#21
(2) INFORMATION FOR SEQ ID NO:16:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 25 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..25
(D) OTHER INFORMATION:
#/note= "primer mTRT.52"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:
CATGTTCATC TAGCGGAAGG AGACA
#
# 25
(2) INFORMATION FOR SEQ ID NO:17:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 33 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..33
(D) OTHER INFORMATION:
#/note= "mF550A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:
ACAGCTGCTT AGATCTTTCG CTTACATCAC AGA
#
# 33
(2) INFORMATION FOR SEQ ID NO:18:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..35
(D) OTHER INFORMATION:
#/note= "mD701A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:
TTGTTAAGGC AGCTGTGACC GGTGCCTATG ATGCC
#
# 35
(2) INFORMATION FOR SEQ ID NO:19:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 38 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..38
(D) OTHER INFORMATION:
#/note= "mD860A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:
TACGTTTTGT TGCTGACTTT CTACTAGTGA CGCCTCAC
#
# 38
(2) INFORMATION FOR SEQ ID NO:20:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..38
(D) OTHER INFORMATION:
#/note= "mD600A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:
GGCATCACCA GGCCACGTGG CTGGCCATGC CCATC
#
# 35
(2) INFORMATION FOR SEQ ID NO:21:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:
Trp Leu Met Ser Val Tyr Val Val Glu Leu L
#eu Arg Ser Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Thr Thr Phe Gln Lys Asn Arg L
#eu Phe Phe Tyr Arg Lys
20
# 25
# 30
Ser Val Trp Ser Lys Leu Gln Ser Ile Gly I
#le Arg Gln His Leu Lys
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:22:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 54 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:22:
Glu Val Arg Gln His Arg Glu Ala Arg Pro A
#la Leu Leu Thr Ser Arg
1 5
# 10
# 15
Leu Arg Phe Ile Pro Lys Pro Asp Gly Leu A
#rg Pro Ile Val Asn Met
20
# 25
# 30
Asp Tyr Val Val Gly Ala Arg Thr Phe Arg A
#rg Glu Lys Arg Ala Glu
35
# 40
# 45
Arg Leu Thr Ser Arg Val
50
(2) INFORMATION FOR SEQ ID NO:23:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:23:
Pro Pro Pro Glu Leu Tyr Phe Val Lys Val A
#sp Val Thr Gly Ala Tyr
1 5
# 10
# 15
Asp Thr Ile Pro Gln Asp Arg Leu Thr Glu V
#al Ile Ala Ser Ile Ile
20
# 25
# 30
Lys Pro
(2) INFORMATION FOR SEQ ID NO:24:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:24:
Lys Ser Tyr Val Gln Cys Gln Gly Ile Pro G
#ln Gly Ser Ile Leu Ser
1 5
# 10
# 15
Thr Leu Leu Cys Ser Leu Cys Tyr Gly Asp M
#et Glu Asn Lys Leu Phe
20
# 25
# 30
Ala Gly Ile
35
(2) INFORMATION FOR SEQ ID NO:25:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:25:
Leu Leu Arg Leu Val Asp Asp Phe Leu Leu V
#al Thr Pro His Leu Thr
1 5
# 10
# 15
His
(2) INFORMATION FOR SEQ ID NO:26:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:26:
Ala Lys Thr Phe Leu Arg Thr Leu Val Arg G
#ly Val Pro Glu Tyr Gly
1 5
# 10
# 15
Cys Val Val Asn Leu Arg Lys Thr Val Val
20
# 25
(2) INFORMATION FOR SEQ ID NO:27:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:27:
His Gly Leu Phe Pro Trp Cys Gly Leu Leu L
#eu
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:28:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:28:
Trp Leu Met Asp Thr Tyr Val Val Gln Leu L
#eu Arg Ser Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Ser Thr Phe Gln Lys Asn Arg L
#eu Phe Phe Tyr Arg Lys
20
# 25
# 30
Ser Val Trp Ser Lys Leu Gln Ser Ile Gly V
#al Arg Gln His Leu Glu
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:29:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 54 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:29:
Glu Val Arg His His Gln Asp Thr Trp Leu A
#la Met Pro Ile Cys Arg
1 5
# 10
# 15
Leu Arg Phe Ile Pro Lys Pro Asn Gly Leu A
#rg Pro Ile Val Asn Met
20
# 25
# 30
Ser Tyr Ser Met Gly Thr Arg Ala Leu Gly A
#rg Arg Lys Gln Ala Gln
35
# 40
# 45
His Phe Thr Gln Arg Leu
50
(2) INFORMATION FOR SEQ ID NO:30:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:30:
Gln Thr Pro Arg Met Tyr Phe Val Lys Ala A
#sp Val Thr Gly Ala Tyr
1 5
# 10
# 15
Asp Ala Ile Pro Gln Gly Lys Leu Val Glu V
#al Val Ala Asn Met Ile
20
# 25
# 30
Arg His
(2) INFORMATION FOR SEQ ID NO:31:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:31:
Arg Cys Tyr Thr Gln Cys Gln Gly Ile Pro G
#ln Gly Ser Ser Leu Ser
1 5
# 10
# 15
Thr Leu Leu Cys Ser Leu Cys Phe Gly Asp M
#et Glu Asn Lys Leu Phe
20
# 25
# 30
Ala Glu Val
35
(2) INFORMATION FOR SEQ ID NO:32:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:32:
Leu Leu Arg Phe Val Asp Asp Phe Leu Leu V
#al Thr Pro His Leu Asp
1 5
# 10
# 15
Gln
(2) INFORMATION FOR SEQ ID NO:33:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:33:
Ala Lys Thr Phe Leu Ser Thr Leu Val His G
#ly Val Pro Glu Tyr Gly
1 5
# 10
# 15
Cys Met Ile Asn Leu Gln Lys Thr Val Val
20
# 25
(2) INFORMATION FOR SEQ ID NO:34:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:34:
His Cys Leu Phe Pro Trp Cys Gly Leu Leu L
#eu
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:35:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:35:
Trp Ile Phe Glu Asp Leu Val Val Ser Leu I
#le Arg Cys Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Gln Gln Lys Ser Tyr Ser Lys T
#hr Tyr Tyr Tyr Arg Lys
20
# 25
# 30
Asn Ile Trp Asp Val Ile Met Lys Met Ser I
#le Ala Asp Leu Lys Lys
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:36:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 25 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:36:
Lys Glu Val Glu Glu Trp Lys Lys Ser Leu G
#ly Phe Ala Pro Gly Lys
1 5
# 10
# 15
Leu Arg Leu Ile Pro Lys Lys Thr Thr
20
# 25
(2) INFORMATION FOR SEQ ID NO:37:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 29 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:37:
Phe Arg Pro Ile Met Thr Phe Asn Lys Lys I
#le Val Asn Ser Asp Arg
1 5
# 10
# 15
Lys Thr Thr Lys Leu Thr Thr Asn Thr Lys L
#eu Leu Asn
20
# 25
(2) INFORMATION FOR SEQ ID NO:38:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:38:
Gly Gln Pro Lys Leu Phe Phe Ala Thr Met A
#sp Ile Glu Lys Cys Tyr
1 5
# 10
# 15
Asp Ser Val Asn Arg Glu Lys Leu Ser Thr P
#he Leu Lys Thr Thr Lys
20
# 25
# 30
Leu Leu
(2) INFORMATION FOR SEQ ID NO:39:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION:* SEQ ID NO:39:
Lys Phe Tyr Lys Gln Thr Lys Gly Ile Pro G
#ln Gly Leu Cys Val Ser
1 5
# 10
# 15
Ser Ile Leu Ser Ser Phe Tyr Tyr Ala Thr L
#eu Glu Glu Ser Ser Leu
20
# 25
# 30
Gly Phe Leu
35
(2) INFORMATION FOR SEQ ID NO:40:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:40:
Leu Met Arg Leu Thr Asp Asp Tyr Leu Leu I
#le Thr Thr Gln Glu Asn
1 5
# 10
# 15
Asn
(2) INFORMATION FOR SEQ ID NO:41:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:41:
Ala Val Leu Phe Ile Glu Lys Leu Ile Asn V
#al Ser Arg Glu Asn Gly
1 5
# 10
# 15
Phe Lys Phe Asn Met Lys Lys Leu Gln Thr
20
# 25
(2) INFORMATION FOR SEQ ID NO:42:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:42:
Gln Asp Tyr Cys Asp Trp Ile Gly Ile Ser I
#le
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:43:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 47 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:43:
Trp Leu Phe Arg Gln Leu Ile Pro Lys Ile I
#le Gln Thr Phe Phe Tyr
1 5
# 10
# 15
Cys Thr Glu Ile Ser Ser Thr Val Thr Ile V
#al Tyr Phe Arg His Asp
20
# 25
# 30
Thr Trp Asn Lys Leu Ile Thr Pro Phe Ile V
#al Glu Tyr Phe Lys
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:44:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:44:
Cys Arg Asn His Asn Ser Tyr Thr Leu Ser A
#sn Phe Asn His Ser Lys
1 5
# 10
# 15
Met Arg Ile Ile Pro Lys Lys Ser Asn Asn
20
# 25
(2) INFORMATION FOR SEQ ID NO:45:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 29 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:45:
Phe Arg Ile Ile Ala Ile Pro Cys Arg Gly A
#la Asp Glu Glu Glu Phe
1 5
# 10
# 15
Thr Ile Tyr Lys Glu Asn His Lys Asn Ala I
#le Gln Pro
20
# 25
(2) INFORMATION FOR SEQ ID NO:46:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:46:
Val Leu Pro Glu Leu Tyr Phe Met Lys Phe A
#sp Val Lys Ser Cys Tyr
1 5
# 10
# 15
Asp Ser Ile Pro Arg Met Glu Cys Met Arg I
#le Leu Lys Asp Ala Leu
20
# 25
# 30
Lys Asn
(2) INFORMATION FOR SEQ ID NO:47:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:47:
Lys Cys Tyr Ile Arg Glu Asp Gly Leu Phe G
#ln Gly Ser Ser Leu Ser
1 5
# 10
# 15
Ala Pro Ile Val Asp Leu Val Tyr Asp Asp L
#eu Leu Glu Phe Tyr Ser
20
# 25
# 30
Glu Phe Lys
35
(2) INFORMATION FOR SEQ ID NO:48:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:48:
Ile Leu Lys Leu Ala Asp Asp Phe Leu Ile I
#le Ser Thr Asp Gln Gln
1 5
# 10
# 15
Gln
(2) INFORMATION FOR SEQ ID NO:49:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:49:
Val Ile Asn Ile Lys Lys Leu Ala Met Gly G
#ly Phe Gln Lys Tyr Asn
1 5
# 10
# 15
Ala Lys Ala Asn Arg Asp Lys Ile Leu Ala
20
# 25
(2) INFORMATION FOR SEQ ID NO:50:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:50:
Lys Glu Leu Glu Val Trp Lys His Ser Ser T
#hr
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:51:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:51:
Trp Leu Tyr Asn Ser Phe Ile Ile Pro Ile L
#eu Gln Ser Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Ser Ser Asp Leu Arg Asn Arg T
#hr Val Tyr Phe Arg Lys
20
# 25
# 30
Asp Ile Trp Lys Leu Leu Cys Arg Pro Phe I
#le Thr Ser Met Lys Met
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:52:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 25 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:52:
Asn Asn Val Arg Met Asp Thr Gln Lys Thr T
#hr Leu Pro Pro Ala Val
1 5
# 10
# 15
Ile Arg Leu Leu Pro Lys Lys Asn Thr
20
# 25
(2) INFORMATION FOR SEQ ID NO:53:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 29 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:53:
Phe Arg Leu Ile Thr Asn Leu Arg Lys Arg P
#he Leu Ile Lys Met Gly
1 5
# 10
# 15
Ser Asn Lys Lys Met Leu Val Ser Thr Asn G
#ln Thr Leu
20
# 25
(2) INFORMATION FOR SEQ ID NO:54:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:54:
Phe Gly Arg Lys Lys Tyr Phe Val Arg Ile A
#sp Ile Lys Ser Cys Tyr
1 5
# 10
# 15
Asp Arg Ile Lys Gln Asp Leu Met Phe Arg I
#le Val Lys Lys Lys Leu
20
# 25
# 30
Lys Asp
(2) INFORMATION FOR SEQ ID NO:55:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:55:
Ser Gln Tyr Leu Gln Lys Val Gly Ile Pro G
#ln Gly Ser Ile Leu Ser
1 5
# 10
# 15
Ser Phe Leu Cys His Phe Tyr Met Glu Asp L
#eu Ile Asp Glu Tyr Leu
20
# 25
# 30
Ser Phe Thr
35
(2) INFORMATION FOR SEQ ID NO:56:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:56:
Leu Leu Arg Val Val Asp Asp Phe Leu Phe I
#le Thr Val Asn Lys Lys
1 5
# 10
# 15
Asp
(2) INFORMATION FOR SEQ ID NO:57:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:57:
Ala Lys Lys Phe Leu Asn Leu Ser Leu Arg G
#ly Phe Glu Lys His Asn
1 5
# 10
# 15
Phe Ser Thr Ser Leu Glu Lys Thr Val Ile
20
# 25
(2) INFORMATION FOR SEQ ID NO:58:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:58:
Lys Lys Arg Met Pro Phe Phe Gly Phe Ser V
#al
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:59:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 4 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:59:
Tyr Tyr Arg Lys
1
(2) INFORMATION FOR SEQ ID NO:60:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 4 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:60:
Gly Ile Pro Gln
1
(2) INFORMATION FOR SEQ ID NO:61:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:61:
Asp Asp Phe Leu Leu
1 5
(2) INFORMATION FOR SEQ ID NO:62:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:62:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:63:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe or
#Trp or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:63:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:64:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 9
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:64:
Xaa Arg Xaa Xaa Pro Lys Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:65:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 7 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:65:
Xaa Arg Xaa Ile Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:66:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#fron Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Cys or Ala"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:66:
Pro Xaa Xaa Xaa Phe Xaa Xaa Xaa Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:67:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Pro or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 16
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:67:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Xaa Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:68:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Lys"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Thr or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:68:
Xaa Xaa Xaa Xaa Xaa Asp Asp Xaa Leu Xaa X
#aa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:69:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 16 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Asn or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:69:
Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Lys Xaa Xaa Xaa
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:70:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 6 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Trp or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or His"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 5
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:70:
Xaa Xaa Xaa Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:71:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:71:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:72:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:72:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:73:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 9
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:73:
Xaa Arg Xaa Xaa Pro Lys Xaa Asp Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:74:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Cys or Ala"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:74:
Pro Glu Xaa Xaa Phe Xaa Xaa Val Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:75:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Pro or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 16
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:75:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Ile Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:76:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Lys"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Thr or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:76:
Xaa Xaa Xaa Leu Xaa Asp Asp Xaa Leu Xaa X
#aa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:77:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 16 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Asn or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:77:
Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Arg Lys Xaa Xaa Xaa
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:78:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:78:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:79:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:79:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:80:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 9
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:80:
Xaa Arg Xaa Xaa Pro Lys Xaa Asn Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:81:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Cys or Ala"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:81:
Pro Arg Xaa Xaa Phe Xaa Xaa Asp Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:82:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Pro or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 16
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:82:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Ser Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:83:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Lys"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:83:
Xaa Xaa Xaa Phe Xaa Asp Asp Xaa Leu Xaa X
#aa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:84:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 16 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Asn or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:84:
Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Gln Lys Xaa Xaa Xaa
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:85:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 5
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:85:
Xaa Xaa Asp Asp Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:86:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 5
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:86:
Xaa Xaa Asp Asp Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:87:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 4 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:87:
Trp Xaa Gly Xaa
1
(2) INFORMATION FOR SEQ ID NO:88:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 6 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:88:
Xaa Leu Gly Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:89:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:89:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:90:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:90:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:91:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gln or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:91:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Trp
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:92:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gln or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:92:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Trp
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:93:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:93:
Leu Arg Xaa Xaa Pro Lys Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:94:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:94:
Xaa Arg Xaa Ile Pro Lys Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:95:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:95:
Xaa Arg Xaa Ile Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:96:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:96:
Xaa Xaa Xaa Xaa Phe Xaa Xaa Xaa Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:97:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:97:
Pro Xaa Leu Tyr Phe Xaa Xaa Xaa Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Ile
(2) INFORMATION FOR SEQ ID NO:98:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:98:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Xaa Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa Xaa Xaa Xaa Xaa Xaa
20
(2) INFORMATION FOR SEQ ID NO:99:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 15 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 14
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:99:
Gln Xaa Xaa Gly Ile Pro Gln Gly Ser Xaa L
#eu Ser Xaa Xaa Leu
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:100:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 13 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:100
#:
Xaa Xaa Xaa Xaa Xaa Xaa Asp Asp Xaa Leu X
#aa Xaa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:101:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:101
#:
Leu Leu Arg Phe Xaa Asp Asp Phe Leu Leu X
#aa Thr
1 5
# 10
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