Thyroid hormone receptors - regulation and function

甲状腺激素受体 - 调节和功能

• 批准号: 8010993
• 负责人: MITCHELL A. LAZAR
• 金额: $ 9.95万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-15 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8010993
• 关键词: Adult; Affect; Arts; Biological; Cardiovascular Diseases; Cell Culture Techniques; Chromatin; Complex; Data; Deacetylase; Development; Diabetes Mellitus; Embryo; Enzymes; Epigenetic Process; Funding; Gene Expression; Gene Targeting; Genetic Transcription; Goals; Histone Deacetylase; Hormone Receptor; Hormones; In Vitro; Inflammation; Knock-out; Knockout Mice; Laboratories; Lead; Ligands; Light; Malignant Neoplasms; Mediating; Metabolic; Metabolic Diseases; Metabolism; Methods; Modeling; Mus; Mutant Strains Mice; Mutation; Nuclear Receptors; Obesity; Pathway interactions; Phenocopy; Phenotype; Physiological; Point Mutation; Property; Protein Isoforms; Regulation; Repression; Role; Silencing Mediator of Retinoid Thyroid Receptor; Specificity; Technology; Testing; Therapeutic Intervention; Thyroid Hormone Receptor; Time; Tissues; Transgenic Organisms; Work; base; gene repression; histone deacetylase 3; in vivo; innovation; insight; member; mutant; novel; prevent; receptor function; recombinase

DESCRIPTION (provided by applicant): Thyroid hormone receptors (TRs) are ligand-dependent, transcriptional regulators of metabolism. TRs repress gene expression in the absence of hormone, which is paradigmatic for other nuclear receptors (NRs) that function as repressors in the unliganded state. Repression is mediated by interaction with corepressors N- CoR (Nuclear Receptor Corepressor) and SMRT (Silencing Mediator of Retinoid and Thyroid receptors), which exist in stoichiometric association with the chromatin-modifiying enzyme, histone deacetylase 3 (HDAC3). HDAC3, in turn, derives its catalytic activity from interacting with N-CoR/SMRT via their unique Deacetylase Activation Domain (DAD). The DAD-dependent N-CoR/SMRT7HDAC3 complex is critical for repression by TR and other NRs in vitro, but the role of this interaction in vivo is unknown. Here we propose to use state of the art methods of gene targeting and mouse phenotyping to test, for the first time, the physiological relevance of the N-CoR7HDAC3 and SMRT7HDAC3 corepressor complexes. We hypothesize that these DAD-dependent interactions are very important, and affect distinct physiological pathways involving NRs. Specific Aim 1 is to determine the physiological function of the N-CoR DAD domain. Knockout of N-CoR is embryonic lethal; we hypothesize that interaction with HDAC3 subserves a subset of N-CoR's developmental and physiological functions. To discover what those functions are, we have generated mice with a point mutation in the N-CoR DAD domain that prevents HDAC3 interaction. Preliminary data demonstrate that mice homozygous for this mutation are viable, with intriguing abnormalities that point to the biological importance of N-CoR7HDAC3. Specific Aim 2 is to determine the physiological function of the SMRT DAD domain. Similar to N-CoR, the physiological role of SMRT7HDAC3 is unknown. We hypothesize that SMRT subserves unique functions that are mediated by HDAC3, and may also have HDAC3-dependent functions that are redundant with those of N-CoR. We will test these hypotheses by generating knockin mice with a point mutation in the SMRT DAD domain. The N-CoR and SMRT homozygous mutant mice, and doubly homozygous mutants, will be carefully analyzed to determine the physiological function of the N-CoR/SMRT7HDAC3 interaction. Specific Aim 3 is to determine the physiological, tissue-specific functions of HDAC3. HDAC3 will be deleted in mice to test the hypothesis that losses of HDAC3 function will phenocopy the doubly homozygous N-CoR/SMRT DAD mutant mice. The HDAC3 knockout will be conditional, enabling us to investigate tissue-specific functions of HDAC3. Together, these innovative and unique studies will elucidate mechanisms regulating transcription repression by TR and other NRs in a physiological context. The insights gained from this work will shed new light on the transcriptional and epigenetic control of key biological pathways, including metabolism and inflammation. This has the potential to lead to new and deeper insights into metabolic disorders, such as obesity, diabetes, and cardiovascular disease, as well as cancer. Relevance: In the past decade, corepressors have emerged as critical regulators of hormone receptors. The proposed studies will innovatively and uniquely elucidate mechanisms regulating the action of hormones and other metabolic regulators. The insights gained from this work will shed new light on key biological pathways, with the potential to lead to new and deeper insights into metabolic disorders, including obesity, diabetes, and cardiovascular disease, as well as cancer.

描述（由申请人提供）：甲状腺激素受体（TR）是配体依赖性的代谢转录调节剂。 TR 在没有激素的情况下抑制基因表达，这对于在未配体状态下充当抑制子的其他核受体 (NR) 来说是典型的。抑制是通过与辅阻遏物 N-CoR（核受体辅阻遏物）和 SMRT（视黄醇和甲状腺受体沉默介体）的相互作用介导的，它们与染色质修饰酶组蛋白脱乙酰酶 3 (HDAC3) 以化学计量关联存在。反过来，HDAC3 通过其独特的脱乙酰酶激活结构域 (DAD) 与 N-CoR/SMRT 相互作用而产生催化活性。 DAD 依赖性 N-CoR/SMRT7HDAC3 复合物对于体外 TR 和其他 NR 的抑制至关重要，但这种相互作用在体内的作用尚不清楚。在这里，我们建议使用最先进的基因靶向和小鼠表型分析方法来首次测试 N-CoR7HDAC3 和 SMRT7HDAC3 辅阻遏物复合物的生理相关性。我们假设这些 DAD 依赖性相互作用非常重要，并且影响涉及 NR 的不同生理途径。具体目标 1 是确定 N-CoR DAD 结构域的生理功能。 N-CoR 的敲除是胚胎致死的；我们假设与 HDAC3 的相互作用促进了 N-CoR 的发育和生理功能的一部分。为了发现这些功能是什么，我们培育了 N-CoR DAD 结构域中具有点突变的小鼠，该突变可阻止 HDAC3 相互作用。初步数据表明，这种突变纯合的小鼠是可行的，其有趣的异常表明了 N-CoR7HDAC3 的生物学重要性。具体目标 2 是确定 SMRT DAD 结构域的生理功能。与 N-CoR 类似，SMRT7HDAC3 的生理作用尚不清楚。我们假设 SMRT 具有由 HDAC3 介导的独特功能，并且还可能具有与 N-CoR 冗余的 HDAC3 依赖性功能。我们将通过生成 SMRT DAD 结构域点突变的敲入小鼠来测试这些假设。将仔细分析 N-CoR 和 SMRT 纯合突变小鼠以及双纯合突变小鼠，以确定 N-CoR/SMRT7HDAC3 相互作用的生理功能。具体目标 3 是确定 HDAC3 的生理、组织特异性功能。将在小鼠中删除 HDAC3，以测试 HDAC3 功能丧失将使双纯合 N-CoR/SMRT DAD 突变小鼠表现出表型的假设。 HDAC3 敲除是有条件的，使我们能够研究 HDAC3 的组织特异性功能。这些创新且独特的研究将共同​​阐明生理背景下 TR 和其他 NR 转录抑制的调节机制。从这项工作中获得的见解将为关键生物途径（包括代谢和炎症）的转录和表观遗传控制提供新的线索。这有可能对肥胖、糖尿病、心血管疾病以及癌症等代谢紊乱产生新的、更深入的见解。 相关性：在过去的十年中，辅阻遏物已成为激素受体的关键调节剂。拟议的研究将以创新和独特的方式阐明调节激素和其他代谢调节剂作用的机制。从这项工作中获得的见解将为关键的生物学途径提供新的线索，并有可能对代谢性疾病（包括肥胖、糖尿病、心血管疾病以及癌症）产生新的、更深入的见解。