AP-2alpha modulates human corticotropin-releasing hormone gene expression in the placenta by direct protein-protein interaction.
Since AP-2alpha induces the expression of hPL, hCG and other syncytiotrophoblast-specific marker genes in cytotrophoblast cells during in vitro differentiation, we have examined whether AP-2alpha also induces hCRH gene expression during differentiation of cytotrophoblast cells. Infection of human cytotrophoblast cells in vitro with an adenovirus expressing AP-2alpha resulted in a twofold increase in hCRH mRNA levels, while infection with an adenovirus expressing a dominant/negative mutant of AP-2alpha inhibited basal hCRH mRNA levels by 40% and completely blocked the induction of hCRH mRNA by AP-2alpha. Transient transfection studies in AtT-20 and HepG2 cells indicated that the induction of hCRH mRNA levels was due, at least in part, to transcriptional activation of the hCRH gene. Gel mobility shift and immunoprecipitation assays strongly suggest that AP-2alpha induces hCRH gene expression by interacting with CREB and not by binding directly to the hCRH promoter.
Cheng
You-Hong
YH
Children's Hospital Medical Center and Department of Pediatrics, Division of Endocrinology, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA. cheny0@chmcc.org
Handwerger
Stuart
S
D001483:Base Sequence; D003346:Corticotropin-Releasing Hormone / Q000235:genetics*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D008969:Molecular Sequence Data; D010920:Placenta / Q000166:cytology / Q000378:metabolism*; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D011485:Protein Binding; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D020218:Response Elements; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D014162:Transfection; D014327:Trophoblasts / Q000378:metabolism
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; C493673:TFAP2A protein, human; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D003346:Corticotropin-Releasing Hormone