Mechanisms of chromatin remodeling at yeast promoters

酵母启动子染色质重塑机制

• 批准号: 8717689
• 负责人: Edward E Luk
• 金额: $ 29.63万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8717689
• 关键词: Address; Antineoplastic Agents; Biochemical; Biochemical Genetics; Biochemistry; Biological; Biological Assay; Cell Cycle; Cell Proliferation; Cell physiology; Cells; Chromatin; Chromatin Remodeling Factor; Chromatin Structure; Complex; DNA; DNA Polymerase II; DNA Sequence; DNA biosynthesis; Deposition; Development; Equilibrium; Excision; Gene Activation; Gene Expression; Gene Expression Regulation; General Transcription Factors; Genes; Genetic Transcription; Genomics; Goals; Grant; Growth; Histones; Human; In Vitro; Kinetics; Label; Lead; Life; Link; Malignant Neoplasms; Measures; Mediating; Modeling; Molecular; Molecular Chaperones; Monitor; Mutation; Nature; Normal Cell; Normal tissue morphology; Nucleosomes; Organism; Outcomes Research; Paper; Pathway interactions; Physiologic pulse; Play; Polymerase; Preparation; Process; Proteins; RNA; Reaction; Recombinants; Regulation; Resolution; Role; S-nitro-N-acetylpenicillamine; Saccharomycetales; Site; Specificity; Staging; System; Testing; Therapeutic Intervention; Time; Transcription Initiation Site; Transcriptional Activation; Variant; Work; Yeast Model System; Yeasts; base; chromatin remodeling; combinatorial; drug development; fly; gene function; genome-wide; histone modification; mutant; novel strategies; overexpression; prevent; promoter; public health relevance; screening; tumor; tumor progression; yeast genetics

DESCRIPTION (provided by applicant): The timing and the extent of gene expression ultimately control normal cell proliferation and cellular differentiation in humans and other organisms. The packaging of eukaryotic DNA with histone proteins into chromatin inhibits virtually all steps in transcription. As such, chromatin functions not only as a platform to regulae transcription, but also as a filter to prevent aberrant transcription. The remodeling of chromatin structure is integral to all stages of transcription. The biological importance of chromatin remodeling in humans is manifested by the fact that mutations in genes important for chromatin remodeling are associated with numerous cancers. The goal of this project is to understand how gene expression occurs in the context of chromatin by elucidating the molecular steps that remodel chromatin structure. The histone variant H2A.Z is a key player in chromatin remodeling. H2A.Z marks gene promoters and has been proposed to help poise genes for transcription by forming nucleosomes that are predisposed for disassembly. However, the mechanism by which H2A.Z nucleosomes are disassembled remains obscure. Previously, I used a combinatorial approach that involves yeast genetics, genomics and biochemistry to dissect the mechanism of H2A.Z deposition. In this project, I will extend the approach to study the disassembly pathway of H2A.Z nucleosomes. One aim is to identify the genes involved by screening mutants that are defective in H2A.Z eviction. These mutants will then be used to study the role of H2A.Z eviction in transcriptional activation. In the second aim, the proteins encoded by these genes will be characterized biochemically in nucleosome eviction assays. Finally, a kinetic approach will be applied to understand how opposing pathways of assembly and disassembly of H2A.Z nucleosomes are maintained in a dynamic equilibrium to prepare genes for transcription. In humans, H2A.Z controls the expression of developmental and cell cycle regulators, and the overexpression of the gene encoding H2A.Z is linked to cancer progression. Given the conserved nature of chromatin structure and its remodeling pathways, the principles developed for the yeast system are likely translatable to humans. This study could lead to the identification of new targets for anticancer drug development.

描述（由申请人提供）：基因表达的时间和程度最终控制人类和其他生物体的正常细胞增殖和细胞分化。真核生物DNA与组蛋白一起包装到染色质中，几乎抑制了转录的所有步骤。因此，染色质不仅作为调节转录的平台，而且作为防止异常转录的过滤器。染色质结构的重塑是转录的所有阶段不可或缺的。染色质重塑在人类中的生物学重要性表现为对染色质重塑重要的基因突变与许多癌症相关。本项目的目标是通过阐明重塑染色质结构的分子步骤来了解基因表达如何在染色质中发生。组蛋白变体H2A.Z是染色质重塑的关键参与者。H2A.Z标记基因启动子，并已被提出通过形成易于拆卸的核小体来帮助平衡基因以进行转录。然而，H2A.Z核小体分解的机制仍然不清楚。在此之前，我使用了一种涉及酵母遗传学、基因组学和生物化学的组合方法来剖析H2A.Z沉积的机制。在这个项目中，我将扩展该方法来研究H2A.Z核小体的分解途径。一个目的是通过筛选在H2A.Z驱逐中有缺陷的突变体来鉴定所涉及的基因。然后将这些突变体用于研究H2A.Z驱逐在转录激活中的作用。在第二个目标中，这些基因编码的蛋白质将在核小体驱逐测定中进行生物化学表征。最后，动力学方法将被应用于了解H2A.Z核小体的组装和拆卸的相对途径如何保持在动态平衡中以准备用于转录的基因。在人类中，H2A.Z控制发育和细胞周期调节因子的表达，编码H2A.Z的基因的过表达与癌症进展有关。鉴于染色质结构及其重塑途径的保守性，为酵母系统开发的原理可能适用于人类。这项研究可能会导致识别 抗癌药物开发的新靶点。