Structural Biology of the Sin3 Corepressor Complex

Sin3 辅阻遏物复合物的结构生物学

• 批准号: 7524862
• 负责人: Ishwar Radhakrishnan
• 金额: $ 27.41万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7524862
• 关键词: Acetylation; Address; Binding; Binding Proteins; Biochemical; Biological; Chromatin; Class; Complex; Condition; Core Assembly; DNA Binding; DNA-Binding Proteins; Defect; Disease; Enzymes; Funding; Future; Gene Expression; Genes; Genetic Transcription; Genome; Goals; Growth and Development function; Hand; Helix (Snails); Histones; Homeostasis; Homologous Gene; Hydrolysis; Investigation; Knock-out; Lead; Malignant Neoplasms; Mammalian Cell; Messenger RNA; Modification; Molecular; Molecular Mechanisms of Action; NMR Spectroscopy; Nature; Nuclear; Pattern; Personal Satisfaction; Play; Process; Proteins; Public Health; Recruitment Activity; Regulation; Role; Signal Transduction; Solutions; Staging; Structure; System; TP53 gene; Techniques; Testing; Transcription Repressor/Corepressor; Translations; Tumor Suppressor Proteins; Work; base; ear helix; histone-binding proteins; improved; insight; neoplastic; promoter; protein function; protein protein interaction; reconstitution; scaffold; size; structural biology; three dimensional structure; tool; transcription factor

DESCRIPTION (provided by applicant): Regulation of eukaryotic gene expression at the transcriptional level relies on the coordinated action of multiple protein factors. The recruitment of multi-subunit coregulator complexes containing chromatin-modifying activities by sequence-specific DNA binding factors and chromatin-binding proteins to specific loci on the genome is an important step in regulating gene transcription. The Sin3 corepressor complex is one of only a handful of major corepressor complexes identified thus far in mammalian cells. The negative influence on gene transcription exerted by this complex relies in part on the action of nuclear histone deacetylases (HDACs), a group of enzymes that catalyze the hydrolysis of acetyl groups from acetylated chromatin substrates. The ~150 kDa Sin3 protein functions both as a molecular scaffold for corepressor complex assembly and interacts directly, or indirectly through other components of the complex, with a surprisingly large and diverse group of DNA-binding transcription factors and chromatin-binding proteins that play important roles in normal growth, development, and cellular homeostasis. Our studies for the next funding period will address questions broadly relating to how components of the Sin3 corepressor complex are recruited by diverse promoter-bound transcription factors on the one hand and by specific patterns of post-translationally modified histones, also referred to as "chromatin marks," on the other. Another major question relates to how the complex is assembled and how it contributes to its functional diversity. Answers to these questions rely on structure-function analyses. The primary tool for the structural investigations will be solution-state NMR spectroscopy because it is ideally suited for studies of transcription factors as they frequently harbor natively unfolded segments and also because of the relatively small size and tractable nature of the systems being studied. In addition, the technique is well-suited for studies of weak interactions such as those involving chromatin-binding modules. Functional analyses will rely on a variety of biochemical and biophysical approaches. The aims of the project broadly focus on three themes: (1) recruitment of the Sin3 corepressor by promoter-bound transcription factors, (2) recruitment and targeting of the corepressor complex to specific chromatin marks and (3) assembly of the core corepressor complex. PUBLIC HEALTH RELEVANCE: The transcription of eukaryotic genes into messenger RNAs for subsequent translation to produce proteins is regulated by a class of proteins known as transcriptional coregulators. These coregulators are recruited to specific regions of the genome by proteins that bind DNA specifically and/or by proteins that bind histones. The molecular interactions involving the Sin3 coregulator and those involving histone-binding proteins that interact with Sin3 are the focus of this proposal because little is known about how these proteins function and because defects in and abnormal amounts of these proteins are associated with diseases such as cancer. The proposed work will attempt to derive detailed molecular pictures of proteins captured in the act of interacting with Sin3 or those of Sin3-interacting proteins captured in the act of interacting with histones, attempt to rationalize how these interactions or lack thereof could lead to diseased states, and provide ideas for developing suitable molecular therapies.

描述（由申请人提供）：转录水平上真核基因表达的调节依赖于多种蛋白质因子的协调作用。通过序列特异性 DNA 结合因子和染色质结合蛋白将含有染色质修饰活性的多亚基辅助调节复合物招募到基因组上的特定位点，是调节基因转录的重要步骤。 Sin3 辅阻遏物复合物是迄今为止在哺乳动物细胞中发现的少数主要辅阻遏物复合物之一。该复合物对基因转录的负面影响部分依赖于核组蛋白脱乙酰酶 (HDAC) 的作用，这是一组催化乙酰化染色质底物乙酰基水解的酶。 ~150 kDa Sin3 蛋白既可作为辅阻遏物复合物组装的分子支架，也可直接或通过复合物的其他成分间接与数量惊人且多样化的 DNA 结合转录因子和染色质结合蛋白相互作用，这些蛋白发挥着重要作用在正常生长、发育和细胞稳态中发挥作用。我们下一个资助期的研究将广泛解决与 Sin3 辅阻遏物复合物的组成部分如何被多种启动子结合的转录因子以及翻译后修饰组蛋白（也称为“染色质”）的特定模式招募相关的问题。标记”，另一方面。另一个主要问题涉及复合体如何组装以及它如何促进其功能多样性。这些问题的答案依赖于结构功能分析。结构研究的主要工具将是溶液态核磁共振波谱，因为它非常适合转录因子的研究，因为它们经常含有天然未折叠的片段，而且还因为所研究的系统的尺寸相对较小且易于处理。此外，该技术非常适合弱相互作用的研究，例如涉及染色质结合模块的相互作用。功能分析将依赖于各种生物化学和生物物理方法。该项目的目标主要集中在三个主题：(1) 通过启动子结合的转录因子招募 Sin3 辅阻遏物，(2) 招募辅阻遏物复合物并将其靶向特定染色质标记，以及 (3) 组装核心辅阻遏物复合物。公共健康相关性：真核基因转录成信使 RNA，随后翻译产生蛋白质，受到一类称为转录共调节子的蛋白质的调节。这些共调节因子通过特异性结合 DNA 的蛋白质和/或结合组蛋白的蛋白质被招募到基因组的特定区域。涉及 Sin3 辅助调节子的分子相互作用以及涉及与 Sin3 相互作用的组蛋白结合蛋白的分子相互作用是该提案的重点，因为人们对这些蛋白质的功能知之甚少，而且这些蛋白质的缺陷和异常数量与癌症等疾病有关。 。拟议的工作将尝试获得在与 Sin3 相互作用的过程中捕获的蛋白质或在与组蛋白相互作用的过程中捕获的 Sin3 相互作用的蛋白质的详细分子图像，试图合理化这些相互作用或缺乏相互作用如何导致疾病状态，并为开发合适的分子疗法提供思路。