Chromatin immunoselection defines a TAL-1 target gene.
Despite the major functions of the basic helix-loop-helix transcription factor TAL-1 in hematopoiesis and T-cell leukemogenesis, no TAL-1 target gene has been identified. Using immunoprecipitation of genomic fragments bound to TAL-1 in the chromatin of murine erythro-leukemia (MEL) cells, we found that 10% of the immunoselected fragments contained a CAGATG or a CAGGTG E-box, followed by a GATA site. We studied one of these fragments containing two E-boxes, CAGATG and CAGGTC, followed by a GATA motif, and showed that TAL-1 binds to the CAGGTG E-box with an affinity modulated by the CAGATG or the GATA site, and that the CAGGTG-GATA motif exhibits positive transcriptional activity in MEL but not in HeLa cells. This immunoselected sequence is located within an intron of a new gene co-expressed with TAL-1 in endothelial and erythroid cells, but not expressed in fibroblasts or adult liver where no TAL-1 mRNA was detected. Finally, in vitro differentiation of embryonic stem cells towards the erythro/megakaryocytic pathways showed that the TAL-1 target gene expression followed TAL-1 and GATA-1 expression. These results establish that TAL-1 is likely to activate its target genes through a complex that binds an E-box-GATA motif and define the first gene regulated by TAL-1.
Cohen-Kaminsky
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S
INSERM, U474, Hématologie Moléculaire, Hôpital Henri Mondor, 51 avenue du Maréchal de Lattre de Tassigny, 94010 Créteil, France.
Maouche-Chrétien
L
L
Vitelli
L
L
Vinit
M A
MA
Blanchard
I
I
Yamamoto
M
M
Peschle
C
C
Roméo
P H
PH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D001665:Binding Sites; D002454:Cell Differentiation; D002843:Chromatin / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006410:Hematopoiesis / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors / Q000378:metabolism*
D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C494688:GATA1 protein, human; C494689:Gata1 protein, mouse; C489366:Tal1 protein, mouse; C067143:TAL1 protein, human