title: CCAAT/enhancer-binding proteins are mediators in the protein kinase A-dependent activation of the decidual prolactin promoter.
abstract: In the course of decidualization, human endometrial stromal cells (ESC) activate the alternative upstream promoter of the decidual prolactin (dPRL) gene. The dPRL promoter is induced by the protein kinase A pathway in a delayed fashion via the region -332/-270 which contains two overlapping consensus binding sequences, B and D, for CCAAT/enhancer-binding proteins (C/EBP). Here we show that sites B and D both bind C/EBPbeta and -delta from ESC nuclear extracts. When decidualization of cultured ESC was induced by treatment with 8-Br-cAMP, complex formation on sites B and D was enhanced. Western blot analysis revealed an elevation of both C/EBPbeta isoforms, liver-enriched activator protein and liver-enriched inhibitory protein, with a delayed onset between 8 and 24 h of cAMP treatment, while C/EBPdelta expression remained unaffected. Cyclic AMP-mediated activation of dPRL promoter construct dPRL-332/luc3 was abrogated by mutation of sites B and D at -310/-285. An expression vector for liver-enriched activator protein potently induced transcription of dPRL-332/luc3 and further enhanced cAMP-mediated induction, while liver-enriched inhibitory protein expression vector abolished the cAMP response, implying that C/EBPs serve as mediators in the delayed cAMP signal transduction to the dPRL promoter. The ratio between activating and repressing isoforms is likely to dictate the transcriptional output.
authors.affiliation: IHF Institute for Hormone and Fertility Research, University of Hamburg, 22529 Hamburg, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Pohnke
authors.forename: R
authors.initials: R
authors.lastname: Kempf
authors.forename: B
authors.initials: B
authors.lastname: Gellersen
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; D019556:COS Cells; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003656:Decidua; D004742:Enhancer Elements, Genetic; D005260:Female; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D011388:Prolactin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D017154:Stromal Cells / Q000187:drug effects / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D012097:Repressor Proteins; D014157:Transcription Factors; D015124:8-Bromo Cyclic Adenosine Monophosphate; D011388:Prolactin; D017868:Cyclic AMP-Dependent Protein Kinases