Regulation of a novel epigenome of protein biosynthesis genes

蛋白质生物合成基因的新型表观基因组的调控

• 批准号: 8885956
• 负责人: STEFAN BEKIRANOV
• 金额: $ 32.39万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8885956
• 关键词: Affect; Anabolism; Architecture; Binding; Biogenesis; Biological Assay; Biological Markers; Bruck-de Lange syndrome; Cancerous; Cell Cycle Progression; Cell Proliferation; Cell division; Cell physiology; Cells; ChIP-seq; Chemicals; Chromatin; Chromatin Remodeling Factor; Chromatin Structure; Chromatin Structure Alteration; Chromosomes; Complex; DNA; DNA Packaging; DNA biosynthesis; DNA replication origin; DNA-Directed RNA Polymerase; Defect; Ensure; Exhibits; Gatekeeping; Gene Expression; Gene Mutation; Generations; Genes; Genetic Materials; Genetic Transcription; Glycolysis; Goals; Growth; Histone H3; Histones; Human; In Vitro; Kinetics; Link; Location; Malignant Neoplasms; Maps; Measures; Mediating; Modeling; Modification; Mutation; Normal Cell; Nucleosomes; Nutrient; Nutritional; Ontology; Organism; Pathway interactions; Phosphorylation; Phosphotransferases; Play; Positioning Attribute; Post-Translational Protein Processing; Process; Proliferating; Property; Protamine Kinase; Protein Biosynthesis; Proteins; Regulation; Relapse; Replication Initiation; Replication Origin; Ribosomal Proteins; Ribosomal RNA; Role; S Phase; Saccharomyces cerevisiae; Signal Transduction; Sirolimus; Sister Chromatid; Site; Testing; Therapeutic; Therapeutic Intervention; Threonine; Transfer RNA; Up-Regulation; Yeasts; cancer cell; cell growth; chromatin remodeling; cohesin; cohesion; crosslink; epigenome; epigenomics; genome-wide; genome-wide analysis; histone modification; in vivo; innovation; inorganic phosphate; novel; novel marker; promoter; protein complex; public health relevance; response; theories; therapeutic target; transcription factor; uncontrolled cell growth

 DESCRIPTION (provided by applicant): DNA templated cellular processes require alteration of chromatin structure to dynamically facilitate access to packaged DNA. The post-translational chemical modification of histone proteins is one critical mechanism that alters chromatin structure either directly or via the recruitment of effector proteins. We have identified a novel histone kinase complex in yeast containing the conserved S-phase replication initiation kinase Cdc7, its activating protein Dbf4, and a number of additional factors. We have found that this complex phosphorylates histone H3 on threonine 45 (H3T45). The site lies at a critical location, where DNA contacts the histone octamer at the entry and exit points of the nucleosome. Therefore, modification of this site has the potential to dramatically alter DNA-histone contacts, providing access for the unwrapping of DNA. Surprisingly, genome- wide studies reveal that H3T45 phosphorylation occurs not only at the expected origins of DNA replication, but it also marks the promoters of specific genes important for cell growth. Furthermore, we find that Cdc7 physically associates with target promoters and is required for RNA polymerase recruitment and full transcription at these locations. The goals of this proposal are to test our hypothesis that the Cdc7-Dbf4 complex establishes an epigenomic state, where under favorable nutritional conditions, the modified chromatin architecture facilitates robust transcription that drives cell growth and proliferation. Furthermore, we will test a model that proposes that the modification, or subsequent nucleosome remodeling, regulates promoter activity via altering the chromatin-binding dynamics of a potential repressor complex. If our hypothesis is correct we will have identified the H3T45 residue as a gatekeeper of the nucleosome, regulating DNA accessibility at target locations for transcription. Importantly, we will have uncovered a novel regulatory network by which gene expression is coordinated to ensure the necessary cell growth that accompanies cell proliferation. Of particular importance, Cdc7 and Dbf4 are misregulated in a variety of cancers and their upregulation is indicative of lower relapse-free survival. As uncontrolled cell growth, division and DNA replication are associated with the proliferation of cancer cells we anticipate that conservation of function of this epigenomic mark will provide a biomarker of diseased states and will offer a highly unique target for cancer therapeutics.

 描述（由申请人提供）： DNA模板化的细胞过程需要改变染色质结构以动态地促进对包装DNA的访问。组蛋白的翻译后化学修饰是直接或通过募集效应蛋白改变染色质结构的一种关键机制。我们已经确定了一种新的组蛋白激酶复合物在酵母中含有保守的S期复制起始激酶Cdc 7，其激活蛋白Dbf 4，和一些额外的因素。我们已经发现，该复合物磷酸化组蛋白H3上的苏氨酸45（H3 T45）。该位点位于一个关键位置，在那里DNA在核小体的入口和出口点接触组蛋白八聚体。因此，该位点的修饰具有显著改变DNA-组蛋白接触的潜力，为DNA的解缠绕提供了途径。令人惊讶的是，全基因组研究表明，H3 T45磷酸化不仅发生在预期的DNA复制起点，而且还标记了对细胞生长重要的特定基因的启动子。此外，我们发现Cdc 7与靶启动子物理相关，并且是RNA聚合酶募集和在这些位置完全转录所需的。该提案的目标是测试我们的假设，即Cdc 7-Dbf 4复合物建立了表观基因组状态，在有利的营养条件下，修饰的染色质结构促进了驱动细胞生长和增殖的稳健转录。此外，我们将测试一个模型，提出修改，或随后的核小体重塑，通过改变潜在的阻遏物复合物的染色质结合动力学调节启动子活性。如果我们的假设是正确的，我们将确定H3 T45残基作为核小体的看门人，调节转录靶位置的DNA可及性。重要的是，我们将发现一个新的调控网络，通过该网络协调基因表达，以确保伴随细胞增殖的必要细胞生长。特别重要的是，Cdc 7和Dbf 4在多种癌症中被错误调节，并且它们的上调指示较低的无复发存活率。由于不受控制的细胞生长、分裂和DNA复制与癌细胞的增殖相关，我们预期这种表观基因组标记的功能的保守将提供疾病状态的生物标志物，并将为癌症治疗提供高度独特的靶标。