Investigation of an unconventional co-repressor complex

非常规共阻遏物复合物的研究

• 批准号: 7213338
• 负责人: Yang Shi
• 金额: $ 28.13万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7213338
• 关键词: Acetylation; Acetylesterase; Address; Adenoviruses; Animals; Binding; Biochemical; Biological Process; Biology; C-terminal; C-terminal binding protein; Caenorhabditis elegans; Cell Nucleus; Cell Proliferation; Chromatin; Complex; DNA; Development; Disruption; Enzymes; Event; Gene Expression Regulation; Genes; Genetic Transcription; HDAC1 gene; Histone Deacetylation; Histone H4; Histones; Homologous Gene; Human; Hydroxy Acids; Investigation; Isomerase; Link; Localized; Mammals; Mass Spectrum Analysis; Mediating; Methylation; Methyltransferase; Modeling; Modification; Molecular; Molecular Genetics; Notch Signaling Pathway; Nuclear; Numbers; Oncogene Proteins; Organism; Oxidoreductase; Play; Point Mutation; Polyamine Catabolism; Polyamines; Polycomb; Protein Binding; Protein C; Proteins; Repression; Research; Role; Sequence Homology; Spermatogenesis; Testing; Testis; Transcriptional Activation; Transcriptional Regulation; Yang; amine oxidase; base; chromatin remodeling; gene repression; histone acetyltransferase; histone methyltransferase; insight; interest; metaplastic cell transformation; mutant; novel; polyamine oxidase; programs; protein function; research study; tumorigenesis; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Transcriptional regulation is a key mechanism that controls fundamental biological processes such as cell proliferation, differentiation and tumorigenesis. The intent of this investigation is to decipher new transcriptional regulatory mechanisms involving a CtBP co-repressor complex. CtBP (C-terminal Binding Protein) was initially identified as a cellular protein that binds the adenoviral E1A oncoprotein. Disruption of this interaction enhances the ability of E1A to induce transformation, suggesting that CtBP may play crucial roles in cellular transformation. CtBP was subsequently shown to function as a transcriptional co-repressor important for animal development. However, detailed molecular events after recruitment of CtBP to DNA were largely unknown. To address this issue, we isolated a CtBP co-repressor complex, which has an unconventional composition consisting of six potential enzymatic activities. These include histone deacetylases and methylases that coordinate histone modifications for repression, a sumo E3 ligase that regulates CtBP subcellular localization, a putative polyamine oxidase (nPAO), which may repress transcription via a novel mechanism, and a histone H4-specific acetylase (HAT) (CDYL) whose role is unclear. We also showed that CtBP, which shares sequence homology with 2-hydroxy acid dehydrogenases (DH), possesses the predicted enzymatic activity. These exciting findings form the basis of this proposal. Unlike the histone modifying enzymes and the sumo E3 ligase, the function and mechanism of action of the dehydrogenase, the putative PAO and the histone H4-specific HAT are unclear, and are the focus of this application. We will use genetic and molecular approaches to delineate the role of CtBP DH activity in transcription and development in C. elegans. We will carry out biochemical and functional tests to investigate the model that nPAO represses transcription via polyamine modification. Current transcription research is focused mainly on histone modifications. The identification of a novel enzyme that regulates transcription by modifying polyamines, the non-histone component of the chromatin, will break new ground for mechanistic considerations. Since acetylation is correlated with transcriptional activation, the association of a HAT (CDYL) with a co-repressor complex is unusual and provides a unique opportunity to address the role of HAT in co-repressor function. Based on our strong initial results, new paradigms are likely to emerge from the proposed studies that will significantly impact our views of eukaryotic gene regulation.

描述（由申请人提供）：转录调控是控制基本生物学过程（如细胞增殖、分化和肿瘤发生）的关键机制。这项调查的目的是破译新的转录调控机制，涉及CtBP共阻遏复合物。CtBP（C-末端结合蛋白）最初被鉴定为结合腺病毒E1 A癌蛋白的细胞蛋白。这种相互作用的破坏增强了E1 A诱导转化的能力，表明CtBP可能在细胞转化中起着至关重要的作用。CtBP随后被证明作为一个转录辅阻遏物的功能，对动物的发展很重要。然而，CtBP募集到DNA后的详细分子事件在很大程度上是未知的。为了解决这个问题，我们分离出一个CtBP共阻遏复合物，它具有一个非常规的组成，由六个潜在的酶活性。这些包括组蛋白去乙酰化酶和甲基化酶，协调组蛋白修饰抑制，sumo E3连接酶，调节CtBP亚细胞定位，推定的多胺氧化酶（nPAO），这可能通过一种新的机制抑制转录，和组蛋白H4特异性乙酰化酶（HAT）（CDYL），其作用尚不清楚。我们还表明，CtBP，它的股票序列同源性与2-羟基酸脱氢酶（DH），具有预测的酶活性。这些令人兴奋的发现构成了这项提议的基础。 与组蛋白修饰酶和sumo E3连接酶不同，脱氢酶、推定的PAO和组蛋白H4特异性HAT的功能和作用机制尚不清楚，并且是本申请的焦点。我们将使用遗传学和分子生物学的方法来阐明CtBP DH活性在C.优美的我们将进行生物化学和功能测试，以研究nPAO通过多胺修饰抑制转录的模型。目前的转录研究主要集中在组蛋白修饰上。鉴定一种通过修饰多胺（染色质的非组蛋白组分）来调节转录的新型酶，将为机制考虑开辟新天地。由于乙酰化与转录激活相关，因此HAT（CDYL）与辅阻遏物复合物的关联是不寻常的，并提供了一个独特的机会来解决HAT在辅阻遏物功能中的作用。基于我们强有力的初步结果，新的范式可能会出现从拟议的研究，将显着影响我们的真核基因调控的观点。