|
|
 Previous Article | Table of Contents | Next Article 
Blood, Vol. 95 No. 11 (June 1), 2000:
pp. 3341-3348
HEMATOPOIESIS
Identification and characterization of a new human ETS-family
transcription factor, TEL2, that is expressed in hematopoietic
tissues and can associate with TEL1/ETV6
Mark D. Potter,
Arjan Buijs,
Brent Kreider,
Luc van Rompaey, and
Gerard C. Grosveld
From the Department of Genetics, St Jude's Children Research
Hospital, Memphis, TN; and Human Genome Sciences, Inc, Rockville, MD.
 |
Abstract |
The ETS family of proteins is a large group of transcription factors
implicated in many aspects of normal hematopoietic development, as well
as oncogenesis. For example, the TEL1/ETV6 (TEL1) gene is
required for normal yolk sac angiogenesis, adult bone marrow hematopoiesis, and is rearranged or deleted in numerous leukemias. This
report describes the cloning and characterization of a novel ETS gene that is highly related to TEL1 and is
therefore called TEL2. The TEL2 gene consists of 8 exons spanning approximately 21 kilobases (kb) in human chromosome
6p21. Unlike the ubiquitously expressed TEL1 gene, however,
TEL2 appears to be expressed predominantly in hematopoietic
tissues. Antibodies raised against the C-terminus of the TEL2 protein
were used to show that TEL2 localizes to the nucleus. All ETS
proteins can bind DNA via the highly conserved ETS domain, which
recognizes a purine-rich DNA sequence with a GGAA core motif. DNA
binding assays show that TEL2 can bind the same consensus DNA binding
sequence recognized by TEL1/ETV6. Additionally, the TEL2
protein is capable of associating with itself and with TEL1 in
doubly transfected Hela cells, and this interaction is mediated through
the pointed (PNT) domain of TEL1. The striking similarities of
TEL2 to the oncogenic TEL1, its
expression in hematopoietic tissues, and its ability to associate with
TEL1 suggest that TEL2 may be an important hematopoietic
regulatory protein.
(Blood. 2000;95:3341-3348)
© 2000 by The American Society of Hematology.
| |
Introduction |
The ETS (E26-transformation specific) family of
transcription factors is a large group of evolutionarily conserved
transcriptional regulators that play an important role in a variety of
cellular processes throughout development and differentiation (reviewed in Dittmer and Nordheim,1 Ghysdael and
Boureux,2 and Sharrocks et al3). All ETS
proteins bind DNA via a highly conserved approximately 85 amino acid
(aa) region, the ETS domain, that recognizes a purine-rich GGAA/T core
motif within the promoters and enhancers of various target genes
(reviewed in Graves and Petersen4 and Janknecht and
Nordheim5). In addition to sequence recognition, DNA
binding may also be regulated through phosphorylation of ETS proteins and by protein-protein interactions mediated via other domains (eg, the
"pointed" [PNT] domain) within ETS proteins, as well as the ETS
domain itself.6,7
Although expressed in a variety of tissues, most currently known
ETS genes are expressed predominantly in hematopoietic cells and many are key regulators of blood cell development and
differentiation.8 Indeed, transgenic and gene-targeting
experiments in the mouse have uncovered essential roles for several ETS
factors in the regulation of various cell lineages within the
hematopoietic system (reviewed in Dittmer and Nordheim1 and
Sharrocks et al3). Additionally, ETS protein binding sites
have been identified in numerous genes involved in the regulation of
the hematopoietic system.2,8
In addition to regulating normal blood cell functions, several ETS
proteins have shown oncogenic potential. For example,
v-ets, the original member of the ETS gene
family, induces avian erythroblastosis when fused to the viral
gag gene and the v-myb oncogene.9 Specific integration of the Friend murine leukemia virus results in
overexpression of either spi1/pu.1 or fli1 in murine
erythroleukemias.10,11 Translocations involving the
ETS gene TEL1/ETV6 (henceforth referred to as
TEL1) are associated with many different human
leukemias.12 Indeed, TEL1 is fused with several
different proteins in both myeloid and lymphoid leukemias and can
contribute to cellular transformation by diverse molecular mechanisms.
Given the extensive involvement of ETS factors in normal hematopoiesis
and in hematopoietic malignancies, a complete understanding of these
complex processes relies on the continued characterization of known
ETS genes, as well as the identification and characterization
of new ETS genes that may also regulate normal and/or aberrant hematopoiesis.
This report describes the identification and initial characterization
of a new human ETS-family gene called TEL2. Analysis of
the TEL2 complementary DNA (cDNA) and the genomic locus shows that TEL2 is closely related to TEL1 in both sequence
and structure. However, in contrast to the ubiquitously expressed
TEL1, TEL2 appears to be expressed predominantly in
hematopoietic tissues. Like a subset of other ETS proteins, including
TEL1, TEL2 contains an amino- (N-) terminal PNT domain and this domain
is thought to mediate protein-protein interactions. We show that TEL2
can associate with itself and with TEL1, and that the PNT domain of TEL1 is crucial for this interaction. Additionally, we show that TEL2
can bind the TEL1 consensus DNA binding sequence (CDBS). Together,
these data describe a new ETS transcription factor closely related to
TEL1 and, in light of the essential role of TEL1 in both normal and
aberrant hematopoiesis, suggest that it likely plays an important role
in hematopoietic regulation.
| |
Materials and methods |
Cloning and sequence analysis
TEL2 was identified by sequencing expressed sequence-tagged
clones (ESTs) from Human Genome Systems (Rockville, MD) libraries as
previously described.13 The TEL2 cDNA sequence was
used for searches of the nonredundant GenBank, EMBL, DDBJ, and PDB
sequence databases and the nonredundant databases of the EST divisions of GenBank, EMBL, and DDBJ, via the Baylor College of Medicine (BCM)
"BLASTN" search engine.14 The TEL2 peptide sequence
was also searched against the GenBank CDS translations, PDB, SwissProt, PIR, and PRF databases through the BCM "BLASTN" search engine. Sequence comparisons with other ETS factors were performed with the
CLUSTAL W Multiple Sequence Alignment Program15 and the Align program.16 The genomic organization of TEL2
was determined by directly comparing the cDNA sequence to the genomic
sequence of PAC clone 50J22 (accession number [acc #] Z84484). The
sequence data of PAC 50J22 were produced by the Chr. 6 Sequencing Group at the Sanger Centre (Hinxton, Cambridge, UK) and can be obtained from
http://www.ncbi.nlm.nih.gov. PAC clone 50J22 was mapped by the Chr. 6 Mapping Group at the Sanger Centre, and the mapping data were obtained
from the World Wide Web at http://www.sanger.ac.uk/HGP/Chr6.
Fluorescent in situ hybridization
The TEL2 cDNA was labeled with digoxigenin-11-dUTP
(Boehringer Mannheim, Indianapolis, IN) by nick translation. The
labeled probe was combined with sheared human DNA and hybridized to
normal metaphase chromosomes derived from PHA-stimulated peripheral
blood lymphocytes in a solution containing 50% formamide, 10% dextran sulfate, and 2 × SSC. Specific hybridization signals were
detected by incubating the hybridized slides in fluorescein-conjugated sheep antibodies against digoxigenin (Boehringer Mannheim). The chromosomes were then counterstained with 4, 6-diamidino-2-phenylindole (DAPI) and analyzed. Band assignment was made by conducting fractional length measurements of 10 specifically hybridized chromosomes 6.
Northern analysis
A human Multiple Tissue Northern (MTN) blot (Clontech, Palo Alto,
CA) containing 2 µg of purified messenger RNA (mRNA) per lane was
hybridized with a randomly primed,
 -32P-dATP-radiolabeled (Amersham Pharmacia Biotech,
Arlington Heights, IL) full-length TEL2 cDNA fragment, and a
similarly labeled human -actin control probe. Hybridization and
washing conditions were according to the manufacturer's
specifications. Blots were exposed on a phosphor screen and imaged on a
Molecular Dynamics Storm 860 phosphorimager (Amersham Pharmacia
Biotech, Sunnyvale, CA).
Antibodies
A decapeptide corresponding to the 10 carboxy-(C)-terminal amino
acids (aa) of TEL2 was synthesized, conjugated to keyhole limpet hemocyanin (KLH), and injected into New Zealand White rabbits (Rockland, Gilbertsville, PA). The KLH-decapeptide used for antibody production contained a 1 amino acid change. The sequence of the KLH-decapeptide, KDKRQEISP, should have been KDKRPEISP. However, all
subsequent assays of the TEL2-specific antibody showed that it
was specific for the TEL2 protein. TEL2-specific antibodies were purified using an AminoLink Plus Immobilization Kit column (Pierce, Rockford, IL), coupled with glutathione-S-transferase (GST)-TEL2 fusion proteins. A monoclonal antibody, 12CA5 (Boehringer Mannheim), was used to recognize influenza hemagglutinin (HA) tagged-TEL2.
Plasmids
Polymerase chain reaction (PCR) products encompassing the
TEL2 full-length cDNA and the TEL2 ETS domain were
inserted in-frame into the EcoRI site of the GST fusion pGEX-2T
vector (Pharmacia, Piscataway, NJ). Primer sequences, including an
introduced-EcoRI site at each 5' end, are as follows:
(full-length TEL2) (sense) 5'-CGGAATTCATATGCAGGAGGGAGAATTG-3'; (antisense)
5'-CGGAATTCCCTCACGGAGAGATTTCTGG-3'; (ETS domain) (sense)
5'-ATCGGAATTCTCTGTTCCTTCCCCGCGATGCC-3'; (antisense) the
same antisense oligomer listed above was used. GST protein preparations
were made by electroporating these pGEX-2T constructs, or the pGEX-2T
vector only, into Escherichia coli BL21 cells. Protein
expression and purification were performed according to manufacturer's
instructions (Pharmacia). The full-length TEL2 cDNA, and a
triple HA-tagged TEL2, were inserted into the cytomegalovirus (CMV) promoter-driven expression vector
pSCTOP.17 All TEL1 constructs used have been previously
described.18 Ten micrograms of each construct were
transfected into Hela cells, 50% to 80% confluent on 10 cmol/L
dishes, using the FuGene 6 Transfection Reagent (Boehringer Mannheim).
Western blotting and immunoprecipitation
For Western blotting, protein lysates were separated on 8%
SDS-polyacrylamide gels (PAGE) and electroblotted onto PVDF membranes (Millipore, Bedford, MA). Kaleidescope Prestained Molecular Weight Standards (Bio-Rad, Hercules, CA) were used as molecular weight markers. Immunoprecipitations were performed as previously
described.19 Blots were blocked overnight in
phosphate-buffered saline (PBS) containing 3% bovine serum albumin
(BSA) and incubated with specific antibodies overnight at 4°C, or 1 hour at room temperature. Bound antibody was detected using alkaline
phosphatase-conjugated antirabbit (for -TEL2) or antimouse (for
12CA5) IgG secondary antibodies and colorimetry (Renaissance Western
Blot Chemiluminescence Reagent; NEN Life Science Products, Boston, MA).
Indirect immunofluorescence analysis
Cytospins were prepared from transfected Hela cells. Cells were
fixed and stained as previously described.18
Images were obtained using confocal microscopy (Olympus
B × 50 laser confocal microscope; Olympus, Lake Success, NY).
Electrophoretic mobility shift assay
The DNA binding assay was performed as previously
described.18
| |
Results |
Identification and sequence analysis of TEL2
TEL2 was identified by sequence comparisons of EST clones
obtained from a human activated T-cell cDNA library. Ten overlapping clones were found that showed homology to ETS transcription factors. Sequences matching these ESTs were also found among clones sequenced from a primary human breast tissue cDNA library and a human meningioma cDNA library (1 clone from each). Alignment of the clones revealed overlapping sequences of 1550 nucleotides (Figure
1). Database searches with the full-length
cDNA sequence showed that it was highly similar to that of the human
TEL1 ETS gene. Therefore, we have named this gene
TEL2.
View larger version (46K):
[in this window]
[in a new window]
| Fig 1.
Nucleotide sequence and predicted amino acid sequence of
TEL2.
Nucleotides are numbered beginning with +1 at the ATG start codon.
Numbering of the aa sequence is italicized. A putative MAPK
phosphorylation site (aa 10-13) is in bold type and italicized. Both
the nucleotide and aa sequences of the PNT (aa 51-117) and ETS (aa
225-304) domains are in bold type and underlined. The last 10 aa of
TEL2, used as a KLH-conjugated peptide for antibody production, are
underlined. The stop codon used and additional in-frame stop codons in
the 3' UTR are italicized and marked with an asterisk. Within the
3' UTR, an attta motif, associated with mRNA turnover, is in bold
type and the putative polyadenylation signal, aataaa, is in bold type
and underlined. This sequence has been assigned the GenBank accession
number AF175387.
|
|
Analysis of this sequence identified an open reading frame (orf) of 341 aa, initiating from an ATG codon 25 base pairs (bp) from the 5'
end of the aligned cDNA sequence. After a stop codon beginning at
position +1027 is a 3' untranslated region (UTR) of 499 bp. The
3' UTR contains additional stop codons, as well as an ATTTA motif
that may be involved in mRNA turnover,20 and a putative
polyadenylation signal 14 bp upstream of a poly (A) sequence.
Sequence comparison of the deduced aa sequence of our cDNA clone to the
aa sequences of over 30 other known ETS genes revealed that it
is most closely related to human TEL1 (data not shown). Indeed,
the deduced 341 aa sequence is 38% identical to the 452 aa sequence of
the TEL1 protein. Although all ETS domains show significant aa sequence
conservation,21 the ETS domains of TEL2 and
TEL1 are highly conserved (85.4% aa identity) (Figure
2A). Comparison of all other ETS domains to
that of TEL2 shows that the next highest level of homology is
with the ETS domains of the Drosophila (D)-YAN (47.6%
aa identity), human ELF1 (44.6% aa identity), and D-E74
proteins (44.6% aa identity) (Figure 2A; data not shown). Sequence
identity of TEL2 to ETS domains from all other ETS
family members examined ranges from approximately 33% to 43% (data
not shown).
View larger version (1213K):
[in this window]
[in a new window]
| Fig 2.
ETS and PNT domains.
Comparison of the aa sequence of the ETS domain (A) and the PNT domain
(B) of human (hu) TEL2 with those of hu-TEL1 and D-YAN.
Identical aa are shaded in black and similar aa are shaded gray. Dashes
represent spaces introduced for optimal alignment. The percentage of aa
identity with TEL2 is shown on the left of each aa sequence.
Comparisons were made using the CLUSTALW program15 and
percentage identity was determined with the ALIGN
program.16
|
|
A subset of ETS transcription factors, including ETS1, ETS2, PNT, GABP,
ERG, FLI1, TEL1, YAN, and ESE1, contains a second highly conserved
domain called the PNT domain (reviewed in Graves and
Petersen4). This domain is thought to mediate
protein-protein interactions.22 A region of approximately
67 aa near the N-terminus of TEL2 is homologous to the PNT domains from
other ETS proteins. Comparison of the TEL2 PNT domain with those of
other ETS factors shows the highest aa identity with TEL1 (62.5%)
(Figure 2B). The next closest match is the D-YAN PNT domain,
which is 48.6% identical to TEL2. Sequence comparisons to all other
ETS-factor PNT domains show an aa identity with TEL2 ranging from
approximately 23% to 39% (data not shown).
The transcriptional activity of several ETS proteins is regulated by
Ras-induced phosphorylation by mitogen-activated protein kinases
(MAPK).7 The sequence of TEL1 contains at least 2 putative MAPK phosphorylation sites, and the protein is phosphorylated in
vivo.23 Analysis of the TEL2 aa sequence reveals the
presence of at least 1 potential MAPK phosphorylation site (Figure 1). This site is located at aa positions 10 to 13, approximately 37 aa
upstream of the PNT domain. No other putative MAPK phosphorylation sites were detected in the TEL2 sequence.
Mapping TEL2 and genomic organization
The chromosomal map position of TEL2 was determined by
fluorescent in situ hybridization (FISH), using a
digoxigenin-11-dUTP-labeled TEL2 cDNA probe hybridized to
normal metaphase human chromosomes (chr) derived from phytohemaglutanin
(PHA)- stimulated peripheral blood lymphocytes. Hybridization signals
were detected on the short arm of chr 6, corresponding to a position of
6p21 (data not shown).
A subsequent BLAST search of GenBank sequences14 using the
TEL2 cDNA sequence identified a perfect match with sequences from PI-derived artificial chromosome (PAC) clone HS50J22 on human chr
6p21, thus confirming our FISH result above. Clone HS50J22 is part of a
bacterial clone contig of human chr 6 generated by the
Sanger Centre Chr 6 Mapping Group (UK), and it has been entirely sequenced (see "Materials and methods"). The complete
TEL2 cDNA sequence is found within this clone; thus, access to
this genomic sequence permitted the deduction of the structural
organization of the TEL2 locus.
The TEL2 cDNA is encoded by at least 8 exons that span
approximately 21 kb of DNA (Table 1). Exon
3 and part of 4 encode the PNT domain and exons 6, 7, and part of 8 encode the ETS domain. Sequences at the borders of the exons and the
sizes of introns and exons are shown in Table 1; however, because the
exact transcriptional start site has not been determined, the exact
size of exon 1 is unknown. As shown in Table 1, all splice junctions
show canonical GT/AG dinucleotides.
TEL2 expressed in hematopoietic tissues
Because several TEL2 cDNA clones were sequenced from an
activated T-cell cDNA library (in addition to a breast tissue and meningioma cDNA library), we anticipated that this gene may be expressed predominantly in hematopoietic tissues. To determine the
expression pattern of TEL2, several human multitissue Northern blots (Clontech) containing poly (A)+ mRNAs from various human tissues
were hybridized with the full-length TEL2 cDNA (Figure 3; data not shown). Expression was seen
only in hematopoietic tissues; 1 predominant band, approximately 1.2 kb, was detected in fetal liver and bone marrow (Figure 3), which is
slightly smaller than the transcript size predicted from the
TEL2 cDNA sequence (approximately 1.5 kb). The same band is
also faintly present in mRNAs isolated from peripheral blood
leukocytes, which may represent expression in activated T cells (Figure
3). Smith and Ostrowski24 have reported a sequence to
Genbank (acc # AF147782), excluding exon 5, identical to TEL2.
A truncated transcript, omitting exon 5 (230 bp) might account for the
smaller band detected in Figure 3. However, a reverse
transcriptase-polymerase chain reaction (RT-PCR) using RNA from human
fetal liver and primers flanking exon 5 yielded only 1 band equal to a
size that includes exon 5 (data not shown). Additionally, Shin et
al26 have reported 3 sequences to Genbank corresponding to
TEL2 (acc # AF116508, AF116509, AF11610), including 2 isoforms
that are 70 to 80 aa shorter than the full-length TEL2.
Therefore, the difference in size of the detected band in Figure 3 and
the TEL2 cDNA may be due to alternative splicing, an unknown
modification(s) of the transcript, or altered migration of the
TEL2 transcript in the denaturing gel.
View larger version (57K):
[in this window]
[in a new window]
| Fig 3.
Expression of TEL2 in human tissues.
A Northern blot containing mRNA from the indicated human tissues was
hybridized sequentially with the full-length TEL2 cDNA and a
control hu -actin probe. The approximate molecular weight (MW) of
the band detected by TEL2 is indicated on the right. The 2.0-kb
band identified by -actin band is also shown.
|
|
Generation of antibodies specific for TEL2
To facilitate further characterization of the TEL2 protein, rabbit
polyclonal antibodies (abys) were generated against a KLH-conjugated decapeptide corresponding to the C-terminal 10 aa of TEL2 (Figure 1).
These 10 aa show significant sequence divergence (8 of 10 different)
from the corresponding 10 aa of TEL1 and, therefore, polyclonal abys
directed against this decapeptide were not expected to cross-react with
the TEL1 protein.
To test the specificity of the TEL2 antisera, we collected lysates from
Hela cells transiently transfected with an HA-tagged TEL2
expression construct (HATEL2). Western blots were made with this
lysate, and lysates from vector-only transfected Hela-cells, and these
blots were screened with either the -TEL2 aby (-T2) or the
HA-specific monoclonal aby 12CA5 (Figure
4A). As shown in Figure 4A, -T2
recognizes the same protein as 12CA5; that is, it specifically binds to
the HATEL2 protein, which is near the predicted size, based on the
predicted 38 kd size of TEL2 plus the 3-kd HA tag.
View larger version (6525K):
[in this window]
[in a new window]
| Fig 4.
TEL2-specific antibodies.
(A) Western blot analysis of TEL2-specific antibodies (-T2). Western
blots containing proteins from the indicated Hela-cell lysates were
made and incubated with either anti-TEL2 antisera (-T2) (left) or an
anti-HA antibody (12CA5) (right). MW standards are indicated in
kilodaltons (kd). (B) Immunoprecipitation of TEL2 with -T2.
Indicated lysates isolated from Hela cells were incubated with -T2.
IP products were separated by SDS-PAGE, Western blotted, and probed
with the 12CA5 aby. MW standards are shown on the right.
|
|
The -TEL2 abys were then tested for their ability to
immunoprecipitate (IP) the TEL2 protein from cellular lysates. The
-T2 aby was incubated with either HATEL2 only or vector
only-transfected Hela-cell lysates. Figure 4B shows that -T2
effectively immunoprecipitates HATEL2 without immunoprecipitating a
significant amount of extraneous proteins. No significant protein is
immunoprecipitated from the vector only-transfected Hela cells.
TEL2 is localized within the nucleus
One mechanism of regulating the activity of transcription factors,
including some ETS factors, is based on subcellular localization of the
protein. For example, the ETS protein D-YAN is regulated by
shuttling between the nucleus and cytoplasm.27 Because TEL2 is closely related to the D-YAN protein, as well as TEL1,
indirect immunofluorescence (IF) was used to study the subcellular
localization of TEL2 in transiently transfected Hela cells.
Hela cells transfected with the HATEL2 expression construct were fixed
to slides by cytospin centrifugation 24 to 48 hours after transfection.
These cells were then incubated with either -T2 or 12CA5. As shown
in Figure 5A, the HATEL2 protein is
localized within the nucleus, excluding the nucleoli. The specificity
of -T2 for TEL2 protein via IF is demonstrated by the identical signal found in cells stained with 12CA5 (Figure 5C), and by the lack
of signal in vector-only transfected cells stained with -T2 or 12CA5
(Figure 5B and 5D, respectively). Thus, the TEL2 protein is capable of
localizing within the nucleus.
View larger version (90K):
[in this window]
[in a new window]
| Fig 5.
Subcellular localization of TEL2 transiently expressed in
Hela cells.
Nuclear staining of TEL2, detected with -T2 and a FITC-conjugated
goat--rabbit secondary aby (A), or with 12CA5 and a FITC-conjugated
goat--mouse secondary aby (C), is shown in cytospin preparations of
transiently transfected Hela cells. Hela cells transfected with an
empty vector expression construct, stained with the same antibodies,
are also shown ([B] and [D], respectively). Original magnification,
×40.
|
|
TEL2 binds to the TEL1 consensus recognition sequence
The CDBS has been determined for several ETS transcription factors
and it is thought that all ETS proteins bind a DNA sequence with a
purine-rich GGAA/T core motif (reviewed in Graves and
Petersen4 and Janknecht and Nordheim5). The
sequences flanking this core are more variable, but not random, and may
confer some binding specificity among ETS proteins. The CDBS for TEL1
has been determined to be ccGGAAgt.18 Because of the high
sequence identity between TEL2 and TEL1, particularly within the ETS
domain, we sought to determine whether the TEL2 protein could bind the
TEL1 CDBS.
Double-stranded oligomers containing the TEL1 CDBS were used in
electrophoretic mobility shift assays (EMSA) to analyze the DNA binding
activities of a GST-fusion TEL2 protein (GST-T2). Because many
full-length ETS proteins do not bind DNA efficiently, due to
intramolecular regulatory mechanisms,28,29 we also
generated a GST fusion of the ETS domain only of TEL2 (GST-T2ETS). As
shown in Figure 6A, GST-T2 does not bind
the TEL1 CDBS. However, the addition of -T2 causes a GST-T2 + DNA + aby complex to shift to the well (Figure 6A). Binding of -T2 likely
changes the intramolecular conformation of GST-T2, allowing the ETS
domain to bind, and a similar phenomenon has been observed in DNA
binding experiments with TEL1.18 Figure 6A also shows that
GST-T2ETS can efficiently bind the TEL1 CDBS, and the addition of
-T2 demonstrates the specificity of this interaction, resulting in a
supershift of the protein-DNA-aby complex. Additionally, the
specificity of the GST-T2ETS+CDBS interaction is demonstrated in Figure
6B. Binding of GST-T2ETS to the 32P-labeled CDBS is
competed away by a molar excess of unlabeled CDBS. Therefore, these
results show that the TEL2 ETS domain is capable of recognizing the
same CDBS as TEL1.
View larger version (5741K):
[in this window]
[in a new window]
| Fig 6.
EMSA analysis of bacterially expressed GST-TEL2 proteins.
(A) Radiolabeled oligomers encoding the TEL1 CDBS were incubated with
eluates of either GST only, GST-T2, or GST-T2ETS proteins. DNA-protein
complexes were supershifted with -T2. Combinations of DNA, protein,
and aby are indicated above each lane. The GST-T2+DNA supershift (top
of figure) and the GST-T2ETS supershift are denoted by arrows labeled
"SS." A complex associated with the addition of -T2 antisera
is denoted with an "*." (B) GST-T2 protein was incubated with
radiolabeled-TEL1 CDBS and increasing amounts of unlabeled TEL1 CDBS.
The molar excess of unlabeled probe added to each binding reaction is
shown above each lane. Complexed and free probe were separated by PAGE
and detected by autoradiography. The GST-T2ETS protein + CDBS probe
complex is indicated with an arrow labeled "P+P." Uncomplexed
probe is shown at the bottom of the figure by the "Probe"-labeled
arrow.
|
|
TEL2 can associate with itself and TEL1.
ETS proteins have been shown to form homodimers and heterodimers with
other ETS proteins, as well as complexes with other proteins outside
the ETS family.22,30-35 The TEL1 protein, for example, can
associate with itself22 and with the ETS protein FLI1,32 via the PNT domain. Because TEL2 contains a PNT
domain, it may also associate with itself and/or other proteins via
this domain. To determine whether TEL2 can self-associate and/or
associate with TEL1, co-IP experiments were performed.
Hela cells were cotransfected with a TEL2 expression construct and
either an HA-TEL2 construct (HAT2), an HA-TEL1 construct (HAT1), or an
HA-TEL1 minus the PNT domain construct (HAT1 PNT). Lysates from cells
transfected with TEL2 + HATEL2 were incubated with 12CA5, and IP
products were separated by SDS-PAGE, Western blotted, and incubated
with -T2. If TEL2 can form homodimers and/or oligomers, then
immunoprecipitation with 12CA5 should IP both HATEL2 and the smaller,
untagged TEL2. Figure 7A shows that TEL2 is
immunoprecipitated with the 12CA5 antibody; therefore TEL2 can
associate with itself. It should be noted that a second band specific
for TEL2 is also immunoprecipitated (Figure 7A). This band may
represent a second isoform of the TEL2 protein, initiating from a
secondary ATG codon. Indeed, TEL1 is expressed in several cell types as
2 protein isoforms, initiating from the ATG codons at position 1 and at
position 43.23
View larger version (846061K):
[in this window]
[in a new window]
| Fig 7.
Coimmunoprecipitation of TEL2.
(A) Coimmunoprecipitation of TEL2 with HATEL2. Human fibroblast cells
(293T) were transiently transfected with empty vector, HAT2, T2, or
HAT2 + T2, and lysates were immunoprecipitated with 12CA5.
Immunocomplexes were separated by SDS-PAGE, Western blotted, and
incubated with -T2. Lysates from cells transfected with the
indicated constructs were also Western blotted with -T2 (right 3 lanes). MW standards are indicated on the left. (B)
Coimmunoprecipitation of TEL2 and TEL1. Lysates of Hela cells
transiently transfected with the indicated expression constructs were
incubated with either -T2 (left 3 lanes) or -T1 antibodies (right
3 lanes). Immunoprecipitates were separated by SDS-PAGE, Western
blotted, and incubated with the 12CA5 aby. MW standards are indicated
on the right. (C) 293T cells were transiently transfected with the
constructs indicated above each lane and lysates were
immunoprecipitated with either -T2 or -T1. Immunoprecipitates
were separated by SDS-PAGE, Western blotted, and incubated with 12CA5.
MW standards are shown on the left.
|
|
Lysates from cells transfected with either TEL2 + HATEL1 or TEL2 + HATEL1 were incubated with -T2, and IP products were subjected to
SDS-PAGE, Western blotted, and incubated with 12CA5. Figure 7B shows
that HAT1 does associate with TEL2. Additionally, Figure 7B shows that
this interaction is mediated through the PNT domain of TEL1. To ensure
that the TEL1 proteins were not specifically being immunoprecipitated
by -T2, this experiment was also performed with Hela cell lysates
from cells cotransfected with HAT2 construct and either a TEL1 or TEL1
minus the PNT domain construct (T1 or T1PNT, respectively). These
lysates were immunoprecipitated with an -TEL1 (-T1)
immunopurified antibody, subjected to SDS-PAGE, and Western blotted
with 12CA5. These results, in Figure 7B, confirm the previous results
(above); that is, the TEL2 protein can interact with the TEL1 protein
via the PNT domain of TEL1.
| |
Discussion |
The data reported here represent the identification and initial
characterization of a new member of the ETS gene family.
Because of its similarity to the ETS gene TEL1, we have
called this gene TEL2. The ETS family of proteins is a large
group of eukaryotic transcription factors that regulate the expression
of target genes involved in a wide variety of cellular functions. The
biologic significance of this group of transcription factors is
underscored by their evolutionary conservation, and by evidence of
disrupted or aberrant expression of ETS proteins in numerous disease
conditions, including cancer.
The ETS family of proteins have been subgrouped on the basis of
sequence comparisons, the position of the ETS domain within each
protein, and the presence of additional protein domains, such as the
PNT domain.2,3,21 Sequence analysis shows that the
TEL2 cDNA encodes a protein of 341 aa that contains a
C-terminal ETS domain, as well as an N-terminal PNT domain. Comparison
of the TEL2 sequence with the sequences of other ETS factors
showed that TEL2 is most closely related to TEL1
(38.2% aa identity). Furthermore, sequence comparisons of the ETS and
PNT domains of TEL2 revealed that they are highly homologous to those
of TEL1 (85.4% and 62.5% aa identity, respectively). Phylogenetic
studies most often group TEL1 with the D-YAN protein and
occasionally the D-ets4 protein.2,3,21 Therefore,
the highly related TEL2 protein described here represents only the
second human ETS sequence in this subgroup.
Further examination of the TEL2 aa sequence reveals a potential MAPK
phosphorylation site located near the N-terminal end of the
protein, approximately 37 aa upstream of the PNT domain. The activity
of several ETS proteins may be regulated by Ras-induced phosphorylation.7 TEL1 contains at least 2 candidate MAPK
sites, and it has been shown to be phosphorylated in
vivo.23 In this context, it is interesting to note that
functional MAPK sites in D-YAN, D-PNT P2, ETS1, and
ETS2 proteins are located in a similar position as the potential TEL2
MAPK site.3,4,7 Additionally, 1 of the putative TEL1 MAPK
sites is located in the same position. Therefore, this phosphorylation
site may represent a conserved regulatory mechanism among some ETS
proteins that is also present in TEL2.
The TEL2 cDNA sequence was discovered to be contained within a
completely sequenced PAC clone on human chr 6p21, confirming our FISH
results. The TEL2 cDNA is composed of at least 8 exons that
span approximately 21 kb of DNA. Comparison of the genomic organization
of TEL2 with that of TEL1 shows striking similarities. Although TEL1 spans over 240 kb of DNA on human chr 12p13, it also is encoded by 8 exons.25 Exon sizes in both genes,
with the exception of exon 5, are nearly identical and encode
homologous regions of each protein. In light of these similarities, it
should be noted that TEL2 is 111 aa shorter than TEL1 (341 aa compared with 452 aa, respectively). Of the 111 aa difference, 105 aa are accounted for in the difference in size of exon 5 of each gene. Interestingly, a putative MAPK phosphorylation site is contained within
the exon 5 encoded sequences of TEL1, which is not present in TEL2.
Although the function (if any) of this phosphorylation site remains to
be determined, it may prove to be significant in comparing the
functions of these 2 related proteins.
Our results show that TEL2 is expressed in human hematopoietic
tissues. Despite regulating a variety of developmental events and being
widely expressed, the majority of known ETS factors are preferentially
expressed in hematopoietic cell lineages8. Gene knock-out
studies in mice have shown that ETS proteins regulate key aspects of
hematopoietic development and differentiation. For example, mice
lacking TEL1 die early in development and have a defect in yolk
sac angiogenesis.36 Additional studies with TEL1-/-embronic stem (ES) cells in chimeric mice showed that
TEL1 is essential for bone marrow hematopoiesis, and may play a
role in hematopoietic stem cell homing.37 Of the tissues
examined, TEL2 is expressed predominantly in fetal liver and
bone marrow. Expression is also faintly detectable in mRNA from
peripheral blood leukocytes. Because TEL2 sequences were
discovered in cDNA libraries made from activated T cells, the band in
peripheral blood leukocyte RNA may represent expression in this cell
type. Thus, given that TEL2 is expressed in hematopoietic
tissues, and its high homology with TEL1, it will be important
to study the role of TEL2 in normal hematopoietic development.
TEL2 is likely expressed in tissues outside the hematopoietic
system, because sequences were also found in cDNA libraries made from
normal human breast tissue and a human meningioma, suggesting that it
is also expressed in these tissues. In fact, database searches with the
TEL2 sequence indicate that it is also present in several cDNA
libraries used by the National Cancer Institute-Cancer Genome Anatomy
Project (NCI-CGAP).38 This is interesting because dysregulation of several ETS genes has been shown to be
oncogenic.1,9,10,39,40 For example, the TEL1 gene
is frequently rearranged in human leukemias of myeloid and lymphoid
origin. Therefore, given that TEL2 is expressed in
hematopoietic tissues, the oncogenic potential of several ETS factors
in general, and in particular, the role of the highly similar
TEL1 in leukemias, it will be of importance to analyze
the oncogenic potential of TEL2. In this light, it is
interesting to note that at least 6 ETSs matching part of the TEL2 sequence were identified from the NCI-CGAP database (data not shown). These clones were sequenced from an RER+ colon tumor (acc # AI343380), pooled germ cell tumors (acc # AA729929), a B-cell chronic
lymphocytic leukemia (acc # AI394727), an adenocarcinoma (acc # AI347001), tonsil tissue enriched for germinal center B cells (acc # AA748867), and an adrenal adenoma (acc # AA604808). The identification
of TEL2 sequences in these tissues may simply represent normal
expression of TEL2 in the tissues from which these tumors are
derived, or may indicate that aberrant expression of TEL2
contributes to the genesis of these malignancies.
It was determined by EMSA that the ETS domain of TEL2 can bind the CDBS
of TEL1. Indeed, ETS domains among the entire family of ETS proteins
are highly homologous and many ETS proteins are able to bind similar
target sequences in vitro.4,5,41 Our sequence comparisons
reveal that 13 of 80 aa residues within the TEL2 ETS domain differ from
the those of the TEL1 ETS domain. Therefore, these aa differences may
differentiate target sequences between these 2 ETS domains. Of course,
differential expression patterns of individual ETS proteins provides
another level of regulation of target genes. TEL1 is ubiquitously
expressed and is therefore likely expressed in the same human tissues
as TEL2 (including fetal liver and bone marrow). Thus, because the TEL2 protein can bind the TEL1 CDBS in vitro, these proteins may have common
gene targets in vivo. However, binding site specificity is likely
determined by a complex formula of criteria and not on target sequences
alone. Furthermore, ETS proteins have been shown to act as both
transcriptional activators and repressors; therefore the
transcriptional activity of common target genes may be differentially
affected by the binding of different ETS factors.
We have shown through co-IP experiments that TEL2 interacts with TEL1.
Protein-protein interactions have been demonstrated with other ETS
proteins and are thought to convey yet another layer of regulation on
the activity of ETS proteins. For example, the ETS protein ERG and its
isoforms have been shown to form homodimers, and heterodimeric
complexes with other ETS proteins via the PNT and ETS domains in
vitro.31 Several ETS proteins, including ERG, ETS1, and
ETS2, have been shown to interact with the AP1 transcription factors
through the ETS domain, and this interaction is required for
transcriptional activity.30 TEL1 also associates with the
ETS protein FLI1.32 The interaction of TEL1 with FLI1 prevents activation of a FLI1 specific promoter and therefore TEL1 may
inhibit the transactivation activity of FLI1. Therefore, it
is significant that TEL2 interacts with TEL1 because it is possible
that the transcriptional activity of both TEL2- and TEL1-target genes
are regulated and/or modulated by this interaction.
Additionally, we have shown by co-IP that TEL2 associates with itself.
Although not shown in this report, it is assumed that the PNT domain is
required for this association. TEL1 is also known to self-associate via
its PNT domain.22 It is through this ability to oligomerize
that many of the TEL1 translocation products form
constitutively active signaling molecules. In addition, TEL1 has
been shown to be a transcriptional repressor and this repression
requires dimerization/oligomerization.42 Therefore, the
ability of TEL2 to self-associate may have important functional consequences.
It is also interesting to note that 2 isoforms of TEL2 are
immunoprecipitated in Figure 7A. TEL1 is also expressed as 2 isoforms.23 There are at least 2 additional ATG codons in
TEL2, at positions 17 and 82, that might initiate a truncated protein.
However, it is assumed that the PNT domain of TEL2 is necessary for
oligomerization; thus, because the smaller isoform is
coimmunoprecipitated with HATEL2, it likely contains the entire PNT
domain. Therefore, the smaller isoform of TEL2 probably initiates from
the ATG at position 17, which would encode a protein that includes the
entire PNT domain.
| |
Acknowledgments |
We are grateful to Virginia Valentine for performing the FISH
analysis. We also thank Andrew Hollenbach, Craig McPherson, Edwin
Meintjes, Ugur Ozbek, and Colin Pritchard for many helpful discussions
of the work. Additionally, we thank Sjozef van Baal, Jacqueline Bonten,
and Wenkai Dou for technical help, and Charlotte Hill for secretarial assistance.
| |
Footnotes |
Submitted August 6, 1999; accepted January 28, 2000.
Supported in part by NCI grant CA-72996-03, the Cancer Center (CORE)
support grant CA-21765, and by the American Lebanese Syrian Associated
Charities (ALSAC) of St Jude Children's Research Hospital.
Reprints: Gerard C. Grosveld, Department of Genetics, St
Jude's Children Research Hospital, 332 N Lauderdale, Memphis, TN.
The publication costs of this
article were defrayed in part by
page charge payment. Therefore,
and solely to indicate this fact,
this article is hereby marked
"advertisement"
in accordance with 18 U.S.C.
section 1734.
| |
References |
1.
Dittmer J, Nordheim A.
Ets transcription factors and human disease.
Biochim Biophys Acta.
1998;1377:F1-F11[Medline]
[Order article via Infotrieve].
2.
Ghysdael J, Boureux A.
The Ets family of transcriptional regulators. In:
Yaniv M,Ghysdael J, eds.
Oncogenes as Transcriptional Regulators. Vol 1. Basel, Switzerland: Birkhauser Verlag; 1997:22.
3.
Sharrocks AD, Brown AL, Ling Y, Yates PR.
The ETS-domain transcription factor family.
Int J Biochem Cell Biol.
1997;29:1371[Medline]
[Order article via Infotrieve].
4.
Graves BJ, Petersen JM.
Specificity within the ETS family of transcription factors.
Adv Cancer Res.
1998;75:1[Medline]
[Order article via Infotrieve].
5.
Janknecht R, Nordheim A.
Gene regulation by Ets proteins.
Biochim Biophys Acta.
1993;1155:346[Medline]
[Order article via Infotrieve].
6.
Crepieux P, Coll J, Stehelin D.
The ETS family of proteins: weak modulators of gene expression in quest for transcriptional partners.
Crit Rev Oncog.
1994;5:615[Medline]
[Order article via Infotrieve].
7.
Wasylyk B, Hagman J, Gutierrez-Hartmann A.
Ets transcription factors: nuclear effectors of the Ras-MAP-kinase signaling pathway.
Trends Biochem Sci.
1998;23:213[Medline]
[Order article via Infotrieve].
8.
Bassuk AG, Leiden JM.
The role of Ets transcription factors in the development and function of the mammalian immune system.
Adv Immuno.
1997;64:65.
9.
Leprince D, Gegonne A, Coll J, et al.
A putative second cell-derived oncogene of the avian leukaemia retrovirus E27.
Nature.
1983;306:395[Medline]
[Order article via Infotrieve].
10.
Ben-David Y, Giddens EB, Letwin K, Bernstein A.
Erythroleukemia induction by Friend murine leukemia virus: insertional activation of a new member of the ets gene family, fli1, closely linked to c-ets1.
Genes Dev.
1991;5:908[Abstract/Free Full Text].
11.
Paul R, Scheutze S, Kozak SL.
The SFPI-1 proviral integration site of Friend erythroleukemia encodes the Ets-related transcription factor PU.1.
J Virol.
1991;65:464[Abstract/Free Full Text].
12.
Golub T, McLean T, Stegmaier K, Carroll M, Tomasson M, Gilliland DG.
The Tel gene and human leukemia.
Biochim Biophys Acta.
1996;1288:M7[Medline]
[Order article via Infotrieve].
13.
Adams M, Dbunick M, Kerlavage A, et al.
Sequence identification of 2375 human brain genes.
Nature.
1992;355:632[Medline]
[Order article via Infotrieve].
14.
Smith R, Wiese B, Wojzynski M, Davison D, Worley K.
BCM search launcher an integrated interface to molecular biology data base search and analysis services available on the World Wide Web.
Genet Res.
1996;6:454.
15.
Thompson J, Higgins D, Gibson T.
CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, positions-specific gap penalties and weight matrix choice.
Nucleic Acids Res.
1994;22:4673[Abstract/Free Full Text].
16.
Pearson W, Lipman D.
Improved tools for biological sequence analysis.
Proc Natl Acad Sci U S A.
1990;85:2444.
17.
Fornerod M, Boer J, van Baal S, et al.
Relocation of the carboxyterminal part of CAN from the nuclear envelope to the nucleus as a result of leukemia-specific chromosome rearrangements.
Oncogene.
1995;10:1739[Medline]
[Order article via Infotrieve].
18. Buijs A, Molijn A, Davis N, et al. The MN1-TEL fusion protein,
resulting from the t(12;22) (p13;q11) in myeloid leukemia, is a
chimeric transcription factor that transforms NIH3T3 cells.
Mol Cell Biol. Submitted.
19.
Hollenbach A, Sublett J, McPherson C, Grosveld G.
The pax3-fkhr oncoprotein is unresponsive to the pax3-associated repressor hdaxx.
EMBO J.
1999;18:3702[Medline]
[Order article via Infotrieve].
20.
Savant BS, Cleveland DW.
Evidence for instability of mRNAs containing AUUUA motifs mediated through translation-dependent assembly of a >20S degradation complex.
Genes Dev.
1992;6:1927[Abstract/Free Full Text].
21.
Laudet V, Hanni C, Stehelin D, Duterque-Coquillaud M.
Molecular phylogeny of the ETS gene family.
Oncogene.
1999;18:1351[Medline]
[Order article via Infotrieve].
22.
Jousset C, Carron C, Boureux A, et al.
A domain of tel conserved in a subset of ets proteins defines a specific oligomerization interface essential to the mitogenic properties of the TEL-PDGFR beta oncoprotein.
EMBO J.
1997;16:69[Medline]
[Order article via Infotrieve].
23.
Poirel H, Oury C, Carron C, et al.
The tel gene products: nuclear phosphoproteins with DNA binding properties.
Oncogene.
1997;14:349[Medline]
[Order article via Infotrieve].
24. Smith J, Ostrowski M. TREF-a tel related Ets factor.
Submitted.
25.
Baens M, Peeters P, Guo C, Aerssens J, Marynen P.
Genomic organization of tel: the human Ets-variant gene 6.
Genet Res.
1996;6:404.
26.
Rebay I, Rubin G.
YAN functions as a general inhibitor of differentiation and is negatively regulated by activation of the Ras1/MAPK pathway.
Cell.
1995;81:857[Medline]
[Order article via Infotrieve].
27.
Lim F, Kraut N, Frampton J, Graf T.
DNA binding by c-Ets1, but not v-Ets, is repressed by an intramolecular mechanism.
EMBO J.
1992;11:643[Medline]
[Order article via Infotrieve].
28.
Wasylyk C, Kerckaert J, Wasylyk B.
A novel modulator domain of Ets transcription factors.
Genes Dev.
1992;6:965[Abstract/Free Full Text].
29.
Basuyaux J, Ferreira E, Stehelin D, Buttice G.
The Ets transcription factors interact with each other and with the c-Fos/c-Jun complex via distinct protein domains in a DNA-dependent and -independent manner.
J Biol Chem.
1997;272:27,188.
30.
Carrere S, Verger A, Flourens A, Stehelin D, Duterque-Coquillaud M.
Erg proteins, transcription factors of the Ets family, form homo, heterodimers and ternary complexes via two distinct domains.
Oncogene.
1998;16:3271.
31.
Kwiatkowski B, Bastian S, Bauer T, Tsai S, Zielinska-Kwiatkowska A, Hickstein D.
The Ets family member Tel binds to the Fli1 oncoprotein and inhibits its transcriptional activity.
J Biol Chem.
1998;273:17,525[Abstract/Free Full Text].
32.
Bassuk A, Leiden J.
A direct physical association between ETS and AP1 transcription factors in normal human T cells.
Immunity.
1995;3:223[Medline]
[Order article via Infotrieve].
33.
Kim W-Y, Sieweke M, Ogawa E, et al.
Mutual activation of ETS1 and AML1 DNA binding by direct interaction of their autoinhibitory domains.
EMBO J.
1999;18:1609[Medline]
[Order article via Infotrieve].
34.
Mao S, Frank R, Zhang J, Miyazaki Y, Nimer S.
Functional and physical interactions between AML1 proteins and an ETS protein, MEF: implications for the pathogenesis of t(8;21)-positive leukemias.
Mol Cell Biol.
1999;19:3635[Abstract/Free Full Text].
35.
Wang L, Kuo F, Fujiwara Y, Gilliland DG, Golub T, Orkin S.
Yolk sac angiogenic defect and intra-embryonic apoptosis in mice lacking the Ets-related factor Tel.
EMBO J.
1997;16:4374[Medline]
[Order article via Infotrieve].
36.
Wang L, Swat W, Fujiwara Y, et al.
The TEL/ETV6 gene is required specifically for hematopoiesis in the bone marrow.
Genes Dev.
1998;12:2392[Abstract/Free Full Text].
37. Strausberg R. Cancer Genome Anatomy Project. Available at:
http://www.ncbi.nlm.nih.gov/ncicap/. Accessed June 10, 1999.
38.
Hromas R, Klemsz M.
The ETS oncogene family in development, proliferation and neoplasia.
Int J Hematol.
1994;59:257[Medline]
[Order article via Infotrieve].
39.
Moreau-Gachelin F, Mattei M-G, Tambourin P, Tavitian A.
The putative oncogene spi: murine chromosomal localization and transcriptional activation in murine acute erythroleukemias.
Oncogene.
1989;4:1449[Medline]
[Order article via Infotrieve].
40.
Shore P, Whitmarsh A, Bhaskaran R, Davis R, Waltho J, Sharrocks A.
Determinants of DNA-binding specificity of ETS-domain transcription factors.
Mol Cell Biol.
1996;16:3338[Abstract].
41.
Lopez R, Carron C, Oury C, Gardellin P, Bernard O, Ghysdael J.
TEL is a sequence-specific transcriptional repressor.
J Biol Chem.
1999;274:30,132[Abstract/Free Full Text].
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
M. G. Roukens, M. Alloul-Ramdhani, S. Moghadasi, M. Op den Brouw, and D. A. Baker
Downregulation of Vertebrate Tel (ETV6) and Drosophila Yan Is Facilitated by an Evolutionarily Conserved Mechanism of F-Box-Mediated Ubiquitination
Mol. Cell. Biol.,
July 1, 2008;
28(13):
4394 - 4406.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Carella, M. Potter, J. Bonten, J. E. Rehg, G. Neale, and G. C. Grosveld
The ETS factor TEL2 is a hematopoietic oncoprotein
Blood,
February 1, 2006;
107(3):
1124 - 1132.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Kawagoe and G. C. Grosveld
MN1-TEL myeloid oncoprotein expressed in multipotent progenitors perturbs both myeloid and lymphoid growth and causes T-lymphoid tumors in mice
Blood,
December 15, 2005;
106(13):
4278 - 4286.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F. Nakamura, Y. Nakamura, K. Maki, Y. Sato, and K. Mitani
Cloning and Characterization of the Novel Chimeric Gene TEL/PTPRR in Acute Myelogenous Leukemia with inv(12)(p13q13)
Cancer Res.,
August 1, 2005;
65(15):
6612 - 6621.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
W. A.G. Stams, M. L. den Boer, H. B. Beverloo, J. P.P. Meijerink, E. R. van Wering, G. E. Janka-Schaub, and R. Pieters
Expression Levels of TEL, AML1, and the Fusion Products TEL-AML1 and AML1-TEL versus Drug Sensitivity and Clinical Outcome in t(12;21)-Positive Pediatric Acute Lymphoblastic Leukemia
Clin. Cancer Res.,
April 15, 2005;
11(8):
2974 - 2980.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Cardone, A. Kandilci, C. Carella, J. A. Nilsson, J. A. Brennan, S. Sirma, U. Ozbek, K. Boyd, J. L. Cleveland, and G. C. Grosveld
The Novel ETS Factor TEL2 Cooperates with Myc in B Lymphomagenesis
Mol. Cell. Biol.,
March 15, 2005;
25(6):
2395 - 2405.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Kawagoe, M. Potter, J. Ellis, and G. C. Grosveld
TEL2, an ETS Factor Expressed in Human Leukemia, Regulates Monocytic Differentiation of U937 Cells and Blocks the Inhibitory Effect of TEL1 on Ras-Induced Cellular Transformation
Cancer Res.,
September 1, 2004;
64(17):
6091 - 6100.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Maki, H. Arai, K. Waga, K. Sasaki, F. Nakamura, Y. Imai, M. Kurokawa, H. Hirai, and K. Mitani
Leukemia-Related Transcription Factor TEL Is Negatively Regulated through Extracellular Signal-Regulated Kinase-Induced Phosphorylation
Mol. Cell. Biol.,
April 15, 2004;
24(8):
3227 - 3237.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. J. Irvin, L. D. Wood, L. Wang, R. Fenrick, C. G. Sansam, G. Packham, M. Kinch, E. Yang, and S. W. Hiebert
TEL, a Putative Tumor Suppressor, Induces Apoptosis and Represses Transcription of Bcl-XL
J. Biol. Chem.,
November 21, 2003;
278(47):
46378 - 46386.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Boccuni, D. MacGrogan, J. M. Scandura, and S. D. Nimer
The Human L(3)MBT Polycomb Group Protein Is a Transcriptional Repressor and Interacts Physically and Functionally with TEL (ETV6)
J. Biol. Chem.,
April 18, 2003;
278(17):
15412 - 15420.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. D. Wood, B. J. Irvin, G. Nucifora, K. S. Luce, and S. W. Hiebert
Small ubiquitin-like modifier conjugation regulates nuclear export of TEL, a putative tumor suppressor
PNAS,
March 18, 2003;
100(6):
3257 - 3262.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. L. Tootle, P. S. Lee, and I. Rebay
CRM1-mediated nuclear export and regulated activity of the Receptor Tyrosine Kinase antagonist YAN require specific interactions with MAE
Development,
March 1, 2003;
130(5):
845 - 857.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Ramachander, C. A. Kim, M. L. Phillips, C. D. Mackereth, C. D. Thanos, L. P. McIntosh, and J. U. Bowie
Oligomerization-dependent Association of the SAM Domains from Schizosaccharomyces pombe Byr2 and Ste4
J. Biol. Chem.,
October 11, 2002;
277(42):
39585 - 39593.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Wasylyk, S. E. Schlumberger, P. Criqui-Filipe, and B. Wasylyk
Sp100 Interacts with ETS-1 and Stimulates Its Transcriptional Activity
Mol. Cell. Biol.,
April 15, 2002;
22(8):
2687 - 2702.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. J. Seidel and B. J. Graves
An ERK2 docking site in the Pointed domain distinguishes a subset of ETS transcription factors
Genes & Dev.,
January 1, 2002;
16(1):
127 - 137.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
X. Gu, B.-H. Shin, Y. Akbarali, A. Weiss, J. Boltax, P. Oettgen, and T. A. Libermann
Tel-2 Is a Novel Transcriptional Repressor Related to the Ets Factor Tel/ETV-6
J. Biol. Chem.,
March 16, 2001;
276(12):
9421 - 9436.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
Top
Abstract
Introduction