A PEBP2 alpha/AML-1-related factor increases osteocalcin promoter activity through its binding to an osteoblast-specific cis-acting element.
To identify osteoblast-specific cis-acting elements and trans-acting factors, we initiated an analysis of the promoter of a mouse osteocalcin gene, an osteoblast-specific gene. In this promoter, we identified two osteoblast-specific cis-acting elements (Ducy, P. and Karsenty, G. (1995) Mol. Cell. Biol. 15, 1858-1869). The sequence of one of these elements, OSE2, is identical to the DNA-binding site of the PEBP2 alpha/AML-1 transcription factors, the mammalian homologues of the Drosophila Runt protein. Here we show, using nuclear extracts, recombinant protein, and a specific antiserum against AML-1 proteins in DNA-binding assays, that one member of this family, AML-1B, binds specifically to OSE2 and is immunologically related to OSF2, the factor present in osteoblast nuclear extracts that binds to OSE2. By DNA cotransfection experiments, we also demonstrate that AML-1B can increase the activity of a short osteocalcin promoter through its binding to OSE2. Lastly, the different mobilities of osteoblast nuclear extract-DNA complexes compared with T-cell nuclear extract-DNA complexes, along with the inability of OSF2 to be upregulated by retinoic acid, unlike the other PEBP2 alpha factors, suggest that OSF2 is a new member of this family of transcription factors. Thus, this study demonstrates that AML-1B can increase gene expression of an osteoblast-specific gene through its binding to an osteoblast-specific cis-acting element and presents evidence that OSF2 is a member of the PEBP2 alpha/AML-1 family of transcription factors.
Geoffroy
V
V
Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Ducy
P
P
Karsenty
G
G
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D050657:Core Binding Factor alpha Subunits; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010006:Osteoblasts / Q000378:metabolism*; D015675:Osteocalcin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D050657:Core Binding Factor alpha Subunits; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D015675:Osteocalcin