The homeodomain protein Pbx1 is involved in cAMP-dependent transcription of human CYP17

Arch Biochem Biophys. 1997 Dec 1;348(1):226-31. doi: 10.1006/abbi.1997.0372.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenal Glands / enzymology
  • Animals
  • Base Sequence
  • Binding Sites
  • Cattle
  • Cell Line
  • Consensus Sequence
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / biosynthesis
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / metabolism*
  • Genes, Reporter
  • Homeodomain Proteins / biosynthesis
  • Homeodomain Proteins / metabolism*
  • Humans
  • Luciferases / biosynthesis
  • Oligodeoxyribonucleotides
  • Pre-B-Cell Leukemia Transcription Factor 1
  • Promoter Regions, Genetic
  • Proto-Oncogene Proteins / biosynthesis
  • Proto-Oncogene Proteins / metabolism*
  • Recombinant Fusion Proteins / biosynthesis
  • Sequence Deletion
  • Steroid 17-alpha-Hydroxylase / biosynthesis*
  • Transcription, Genetic*
  • Transcriptional Activation
  • Transfection
  • Tumor Cells, Cultured

Substances

  • DNA-Binding Proteins
  • Homeodomain Proteins
  • Oligodeoxyribonucleotides
  • Pre-B-Cell Leukemia Transcription Factor 1
  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • pbx1 protein, human
  • Cyclic AMP
  • Luciferases
  • Steroid 17-alpha-Hydroxylase
  • Cyclic AMP-Dependent Protein Kinases