title: Gene regulation by thyroid hormone.
abstract: Regulation of gene expression by thyroid hormones (T3, T4) is mediated via thyroid hormone receptors (TRs). TRs are DNA-binding transcription factors that function as molecular switches in response to ligand. TRs can activate or repress gene transcription depending on the promoter context and ligand-binding status. In most cases, in the absence of ligand, TRs interact with a corepressor complex containing histone deacetylase activity, which actively inhibits transcription. The binding of ligand triggers a conformational change in the TR that results in the replacement of the corepressor complex by a coactivator complex containing histone acetyltransferase activity, through which the chromatin structure is remodeled, thereby leading to activation of transcription. In addition, the finding that several TR-interacting coregulators act more directly on the basal transcriptional machinery suggests that mechanisms independent of histone acetylation and deacetylation also are involved in TR action.
authors.affiliation: Division of Endocrinology and Metabolism and Program in Cellular and Molecular Biology, University of Michigan Medical Center, 5560 MSRB-II, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0678, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: R J
authors.initials: RJ
authors.lastname: Koenig
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D006801:Humans; D011988:Receptors, Thyroid Hormone / Q000235:genetics / Q000502:physiology; D013963:Thyroid Hormones / Q000235:genetics / Q000502:physiology*
chemical_list: D011988:Receptors, Thyroid Hormone; D013963:Thyroid Hormones