title: The N-CoR complex enables chromatin remodeler SNF2H to enhance repression by thyroid hormone receptor.
abstract: Unliganded thyroid hormone receptor (TR) actively represses transcription via the nuclear receptor corepressor (N-CoR)/histone deacetylase 3 (HDAC3) complex. Although transcriptional activation by liganded receptors involves chromatin remodeling, the role of ATP-dependent remodeling in receptor-mediated repression is unknown. Here we report that SNF2H, the mammalian ISWI chromatin remodeling ATPase, is critical for repression of a genomically integrated, TR-regulated reporter gene. N-CoR and HDAC3 are both required for recruitment of SNF2H to the repressed gene. SNF2H does not interact directly with the N-CoR/HDAC3 complex, but binds to unacetylated histone H4 tails, suggesting that deacetylase activity of the corepressor complex is critical to SNF2H function. Indeed, HDAC3 as well as SNF2H are required for nucleosomal organization on the TR target gene. Consistent with these findings, reduction of SNF2H induces expression of an endogenous TR-regulated gene, dio1, in liver cells. Thus, although not apparent from studies of transiently transfected reporter genes, gene repression by TR involves the targeting of chromatin remodeling factors to repressed genes by the HDAC activity of nuclear receptor corepressors.
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6149, USA.
authors.forename: Theresa
authors.initials: T
authors.lastname: Alenghat
authors.forename: Jiujiu
authors.initials: J
authors.lastname: Yu
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Lazar
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000235:genetics; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D056971:Nuclear Receptor Co-Repressor 1; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D011988:Receptors, Thyroid Hormone / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000099186:Histone Deacetylase 3
chemical_list: D000251:Adenosine Triphosphatases; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D006655:Histone Deacetylases; D006657:Histones; D008156:Luciferases; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D011988:Receptors, Thyroid Hormone; D012097:Repressor Proteins; D014157:Transcription Factors; D000099186:Histone Deacetylase 3; C518584:DIDO1 protein, human; C539127:NCOR1 protein, human; C539128:Ncor1 protein, mouse; C409462:SMARCA5 protein, human