title: Ets-2 and components of mammalian SWI/SNF form a repressor complex that negatively regulates the BRCA1 promoter.
abstract: Ets-2 is a transcriptional activator that can be modulated by ras-dependent phosphorylation. Evidence is presented indicating that ets-2 can also act as a transcriptional repressor. In the breast cancer cell line MCF-7, exogenous ets-2 repressed the activity of a BRCA1 promoter-luciferase reporter dependent on a conserved ets-2-binding site in this promoter. Conditional overproduction of ets-2 in MCF-7 cells resulted in repression of endogenous BRCA1 mRNA expression. To address the mechanism by which ets-2 could act as a repressor, a biochemical approach was used to identify proteins that interacted with the ets-2 pointed domain. From this analysis, components of the mammalian SWI/SNF chromatin remodeling complex were found to interact with ets-2. Brg-1, the ATP-hydrolyzing component of the SWI/SNF complex, along with the BAF57/p50 and Ini1 subunits could be co-immunoprecipitated from cells with ets-2. The pointed domain of ets-2 directly interacted in vitro with the C-terminal region of Brg-1 in a phosphorylation-dependent manner. The combination of Brg-1 and ets-2 could repress the BRCA1 promoter reporter in transfection assays. These results support a role for ets-2 as a repressor and indicate that components of the mammalian SNF/SWI complex are required as co-repressors.
authors.affiliation: Department of Molecular Genetics and The Comprehensive Cancer Center, Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Baker
authors.forename: Guo
authors.initials: G
authors.lastname: Wei
authors.forename: Alicia Erbe
authors.initials: AE
authors.lastname: Schaffner
authors.forename: Michael C
authors.initials: MC
authors.lastname: Ostrowski
mesh_terms: D016475:3T3 Cells; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002843:Chromatin / Q000378:metabolism; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D019398:Genes, BRCA1; D006801:Humans; D006868:Hydrolysis; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; C107465:ERF protein, human; C494069:ETS2 protein, human; C494070:Ets2 protein, mouse; D009687:Nuclear Proteins; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D008156:Luciferases; C084108:SMARCA4 protein, human; C513194:Smarca4 protein, mouse; D004265:DNA Helicases