The bovine CYP17 promoter contains a transcriptional regulatory element cooperatively bound by tale homeodomain proteins.
Bovine CYP17 is regulated at the transcriptional level by ACTH acting through the second messenger cAMP in adrenal fasciculata and reticularis cells. Promoter analysis has previously identified two regions, proximal and distal, within the CYP17 promoter important in the cAMP dependent transcriptional regulation of this gene. The proximal (-80 to -40) cAMP responsive sequence (CRS2) has been identified as a binding site for Steroidogenic Factor-1 (SF-1)/Ad4BP. The distal region (-243 to -100) is also important for the cAMP transcriptional response as revealed by deletion analysis. Within this distal region from -243 to -225, an independent cAMP responsive sequence referred to as CRS1 has been described. The transcription factors binding CRS1 have been identified as homeodomain transcription factors belonging to an atypical class of homeodomain proteins referred to as TALE. Two families of homeodomain proteins which bind CRS1 are the Pbx and Meis1 families. Proteins from neither of these families can bind CRS1 individually; however, members of the Pbx family interact with members of the Meis1 family to cooperatively bind this element. CRS1 was the first identified cis-acting target element for members of both the Pbx and Meis1 family. Unlike SF-1, these proteins are not expressed in a steroidogenic tissue-specific manner but rather, appear ubiquitous. A current model for the function of these proteins in CYP17 regulation is that they may enhance the cAMP response through the downstream SF-1 binding site.
Bischof
L J
LJ
Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
Kagawa
N
N
Waterman
M R
MR
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002417:Cattle; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D011994:Recombinant Proteins; D012156:Reticulocytes / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics*; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000235:genetics*; D014407:Tumor Cells, Cultured
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C000616391:MEIS1 protein, human; C000616392:Meis1 protein, mouse; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; C515057:NR5A1 protein, human; D009363:Neoplasm Proteins; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C083400:PBX1 protein, human; C515058:steroidogenic factor 1, mouse; D013254:Steroid 17-alpha-Hydroxylase