The homeodomain protein Pbx1 is involved in cAMP-dependent transcription of human CYP17.
Pbx1 is a homeodomain transcription factor involved in cAMP-dependent transcriptional regulation of the bovine CYP17 gene. In this study, we have investigated the involvement of Pbx1 in the transcriptional regulation of the human CYP17 gene. Although a sequence identical to previously determined Pbx-binding sites is not present in the promoter region of the human CYP17 gene, three putative Pbx-binding sites are identified by sequence similarity analysis. Coexpression of Pbx1 and a catalytic subunit of protein kinase A (PKA) greatly enhances reporter gene transcription via the 5'-flanking region of the human CYP17 gene. Upon gel shift analysis utilizing nuclear extracts from human adrenal H295R cells, one of the three putative Pbx1-binding sites, -250/-241 bp, shows the typical intense doublet observed with other Pbx-binding sites. 5'-Deletion analyses of the reporter construct containing this Pbx-binding site showed approximately sixfold induction by coexpression of Pbx1 and PKA compared to the basal transcription, suggesting that Pbx1 binds the -250/-241 bp sequence and participates in cAMP-dependent regulation of the human CYP17 gene.
Ogo
A
A
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA.
Waterman
M R
MR
McAllister
J M
JM
Kagawa
N
N
D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002417:Cattle; D002460:Cell Line; D016384:Consensus Sequence; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000096:biosynthesis / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D008156:Luciferases / Q000096:biosynthesis; D009838:Oligodeoxyribonucleotides; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D013254:Steroid 17-alpha-Hydroxylase / Q000096:biosynthesis*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009838:Oligodeoxyribonucleotides; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; C083400:PBX1 protein, human; D000242:Cyclic AMP; D008156:Luciferases; D013254:Steroid 17-alpha-Hydroxylase; D017868:Cyclic AMP-Dependent Protein Kinases