title: A p300 protein as a coactivator of GATA-6 in the transcription of the smooth muscle-myosin heavy chain gene.
abstract: The mechanisms that regulate smooth muscle development and differentiation are poorly understood. Although recent studies have suggested the possible role of a zinc finger transcription factor, GATA-6, in the differentiation of vascular smooth muscle cells (VSMCs), the downstream gene targeted by GATA-6 is unknown. The expression of smooth muscle-myosin heavy chain (Sm-MHC) provides a highly specific marker for the differentiated phenotype of VSMCs as well as the smooth muscle cell lineage. Here, we show that GATA-6 bound to a GATA-like motif (-810/-805) within the rat Sm-MHC promoter in a sequence-specific manner and activated this promoter through this site. In addition, we show that the transcriptional coactivator p300 associated with GATA-6 during the transcription of the Sm-MHC gene. A p300/GATA-6 complex in VSMCs was up-regulated by induction of the quiescent phenotype. A wild-type E1A, which interferes with endogenous p300, but not a mutant E1A defective for p300 binding, markedly down-regulated the expression of endogenous Sm-MHC in quiescent-phenotype VSMCs. These studies provide the first identification of a functionally important GATA-6 binding site within a smooth muscle-specific promoter and suggest a role for p300 in the maintenance of the differentiated phenotype in VSMCs as a coactivator of GATA-6.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Wada
authors.forename: K
authors.initials: K
authors.lastname: Hasegawa
authors.forename: T
authors.initials: T
authors.lastname: Morimoto
authors.forename: T
authors.initials: T
authors.lastname: Kakita
authors.forename: T
authors.initials: T
authors.lastname: Yanazume
authors.forename: S
authors.initials: S
authors.lastname: Sasayama
mesh_terms: D017500:Adenovirus E1A Proteins / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D019556:COS Cells; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D050881:E1A-Associated p300 Protein; D050993:GATA6 Transcription Factor; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000737:chemistry*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051381:Rats; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation
chemical_list: D017500:Adenovirus E1A Proteins; D004268:DNA-Binding Proteins; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D008156:Luciferases; D015500:Chloramphenicol O-Acetyltransferase; D050881:E1A-Associated p300 Protein; C494362:Ep300 protein, rat; D018995:Myosin Heavy Chains