Mechanism of Epigenetic Inheritance

表观遗传机制

• 批准号: 10447571
• 负责人: Zhiguo Zhang
• 金额: $ 84.67万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10447571
• 关键词: Address; Binding Proteins; Cell Cycle; Cell physiology; Cells; Chromatin; Complex; Coupled; DNA; DNA biosynthesis; DNA replication fork; Elements; Endogenous Retroviruses; Epigenetic Process; Euchromatin; Eukaryotic Cell; Genomic DNA; Heterochromatin; Higher Order Chromatin Structure; Histone H3; Histones; Immunotherapy; Inherited; Lead; Light; Link; Methods; Modification; Molecular; Mus; Nucleosomes; Peptide Sequence Determination; Process; Repression; S phase; Yeasts; base; cancer cell; daughter cell; embryonic stem cell; genome integrity; histone modification; insight; novel; response; transmission process

In eukaryotic cells, genomic DNA is packaged into chromatin that encodes epigenetic information and maintain genome integrity. Chromatin is further organized into distinct functional domains, such as heterochromatin and euchromatin, that contain different post-translational histone modifications (PTM). How different chromatin states are inherited during S phase of the cell cycle is one of the most challenging questions in the chromatin and epigenetic fields. The “first” step in this complex process is the assembly of replicated DNA into nucleosomes using both parental and newly-synthesized histones in a process that is tightly coupled to ongoing DNA synthesis. We have been studying how nucleosomes are formed following DNA replication and have made multiple major contributions to this process. However, how parental histone (H3-H4)2 tetramers, the primary carrier of epigenetic modifications, are transferred to replicating DNA is still poorly understood, which hinders our understanding of the transmission of epigenetic information into daughter cells. The major challenge to understanding parental histone (H3-H4)2 assembly is a lack of methods to track this process. We have developed the eSPAN (enrichment and Sequencing Protein- Associated Nascent DNA) method that can discern whether a protein binds to leading or lagging strands of DNA replication forks in both yeast and mouse embryonic stem (ES) cells. This method makes it possible to identify factors that function in nucleosome assembly of parental histone (H3- H4)2. Moreover, we discovered that cells defective in parental histone transfer compromise the repression of endogenous retrovirus (ERVs), repetitive DNA elements that are normally silenced via a heterochromatin-based mechanism. Others show that ERV reactivation in cancer cells leads to increased response to immunotherapy. In this proposal, we will elucidate the molecular mechanisms whereby parental (H3-H4)2 are reassembled into nucleosomes following DNA replication in yeast and mouse ES cells and determine how deficiencies in this process impact ERV silencing. Together, these studies will address fundamental questions regarding chromatin replication and epigenetic inheritance, while also providing novel insights into a major epigenetic mechanism that boosts the response of cancer cells to immunotherapy.

在真核细胞中，将基因组DNA包装到染色质中，该染色质编码表观遗传信息并维持 基因组完整性。染色质进一步组织为不同的功能域，例如异染色质和 全染色质，其中包含不同的翻译后Hisstone修饰（PTM）。不同的染色质如何 在细胞周期的S阶段继承是染色质中最挑战的问题之一， 表观遗传场。这个复杂过程中的“第一”步骤是将复制的DNA组装成核小体 在与持续的DNA合成的过程中，同时使用亲本和新合成的组蛋白。 我们一直在研究DNA复制后如何形成核小体，并使多个主要 对此过程的贡献。但是，父母组蛋白如何（H3-H4）2四聚体，这是表观遗传的主要载体 修改被转移到复制DNA的转移仍然很少了解，这阻碍了我们对 将表观遗传信息传播到子细胞中。理解父母的主要挑战 Hisstone（H3-H4）2组件缺乏跟踪此过程的方法。我们已经开发了Espan （富集和测序蛋白 - 与新生的DNA）方法，可以辨别蛋白质是否存在 与酵母和小鼠胚胎茎（ES）细胞中DNA复制叉的前导或滞后链结合。 这种方法可以鉴定出在亲本组蛋白核小体组装中起作用的因素（H3-- H4）2。此外，我们发现亲本组蛋白转移中有缺陷的细胞损害了 内源性逆转录病毒（ERV），重复的DNA元素，通常通过基于异染色质沉默 机制。其他人则表明，癌细胞中的ERV重新激活导致对免疫疗法的反应增加。 在此提案中，我们将阐明父母（H3-H4）2的分子机制。 在酵母和小鼠ES细胞中DNA复制后的核小组，并确定在此中缺乏 过程影响ERV沉默。这些研究将共同​​解决有关染色质的基本问题 复制和表观遗传遗传，同时还为主要的表观遗传机制提供新的见解 这增加了癌细胞对免疫疗法的反应。