Transcription factor GATA-1 regulates human HOXB2 gene expression in erythroid cells.
The human HOXB2 gene is a member of the vertebrate Hox gene family that contains genes coding for specific developmental stage DNA-binding proteins. Remarkably, within the hematopoietic compartment, genes of the HOXB complex are expressed specifically in erythromegakaryocytic cell lines and, for some of them, in hematopoietic progenitors. Here, we report the study of HOXB2 gene transcriptional regulation in hematopoietic cells, an initial step in understanding the lineage-specific expression of the whole HOXB complex in these cells. We have isolated the HOXB2 5'-flanking sequence and have characterized a promoter fragment extending 323 base pairs upstream from the transcriptional start site, which, in transfection experiments, was sufficient to direct the tissue-specific expression of HOXB2 in the erythroid cell line K562. In this fragment, we have identified a potential GATA-binding site that is essential to the promoter activity as demonstrated by point mutation experiments. Gel shift analysis revealed the formation of a specific complex in both erythroleukemic lines K562 and HEL that could be prevented by the addition of a specific antiserum raised against GATA-1 protein. These findings suggest a regulatory hierarchy in which GATA-1 is upstream of the HOXB2 gene in erythroid cells.
Vieille-Grosjean
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I
INSERM, unité 217, Département de Biologie Moléculaire et Structurale, Centre d'Etudes Nucléaires, Grenoble, France.
Huber
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P
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D005091:Exons; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010641:Phenotype; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D015342:DNA Probes; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C086061:HOXB2 protein, human; D018398:Homeodomain Proteins; D014157:Transcription Factors