Defining the Roles of Polycomb Repressive Complex 2 (PRC2) Subcomplexes in H3 K27M Gliomas

项目摘要/摘要 细胞类型特异的基因表达是复杂多细胞生命的基础，是通过包装一个 常见的、不变的基因组转化为更高级别的染色质结构，具有无数的调控水平。共价后- 特定组蛋白残基上的翻译修饰(PTM)是动态调节的主要点。 在整个发育过程中进行修改，以确保适当的组织谱系规范、细胞命运转换和 维护小区身份。组蛋白修饰物以及组蛋白底物本身的突变， 这是包括癌症在内的多种人类疾病的基础。27位氨基酸残基反复发生的赖氨酸到蛋氨酸突变 组蛋白H3(H3K27M)在80%的弥漫性固有桥脑胶质瘤(DIPG)中发现，这是一种高级别的儿科肿瘤 预后不佳的脑癌。H3K27M癌组蛋白部分通过抑制作用驱动神经胶质瘤的形成 多梳抑制复合体2(PRC2)，负责甲基化H3K27的甲基转移酶复合体， 导致抑制标记H3K27me3的全基因组缺失。 这项建议致力于解决H3K27M驱动的PRC2长期观察但特征不佳的一个方面 调节失调：H3K27me3焦点部位残留的PRC2活性。利用生化、基因组和细胞- 基于方法，本研究中描述的实验试图定义PRC2亚基 靶向DIPG细胞中PRC2募集的位点并在其上进行催化活性。这些结果将显著地 加深对H3K27M-染色质异常的理解，并可能揭示H3的可利用漏洞 K27M弥漫性胶质瘤。 本提案中概述的培训计划将在威斯康星大学麦迪逊分校进行，时间为 拥有尖端资源、设施和活力的良好院校研究环境 协作的机会。在专家指导和指导下，执行这项培训计划 癌症生物学、染色质生物化学、蛋白质组学和基因组学领域的合作者将提供 无价之宝基金会旨在开启一段成功的职业生涯，成为一名内科科学家兼癌症研究人员。

PROJECT ABSTRACT/SUMMARY Cell type-specific gene expression, the basis for complex multicellular life, is achieved through packaging a common, invariant genome into higher-order chromatin structures with myriad levels of regulation. Covalent post- translational modifications (PTMs) at specific histone residues are major points of regulation that are dynamically modified throughout development to ensure proper tissue lineage specification, cell fate transitions, and maintenance of cell identity. Mutations in histone modifiers, as well as the histone substrates themselves, underlie a variety of human diseases including cancer. Recurrent lysine-to-methionine mutations at residue 27 of histone H3 (H3 K27M) are found in >80% of diffuse intrinsic pontine gliomas (DIPG), a high-grade pediatric brain cancer with dismal prognosis. The H3 K27M oncohistone drives gliomagenesis in part through its inhibition of polycomb repressive complex 2 (PRC2), the methyltransferase complex responsible for methylating H3K27, resulting in genome-wide depletion of the repressive mark H3K27me3. This proposal endeavors to address a long-observed yet poorly characterized aspect of H3K27M-driven PRC2 dysregulation: residual PRC2 activity at focal sites of H3K27me3. Leveraging biochemical, genomic, and cell- based approaches, the experiments described in this study seek to define the PRC2 subunits necessary for targeting to, and catalytic activity at, sites of PRC2 recruitment in DIPG cells. These results stand to significantly deepen our understanding of H3K27M-dysregulated chromatin and may reveal exploitable vulnerabilities for H3 K27M diffuse gliomas. The training plan outlined in this proposal will be performed at the University of Wisconsin-Madison within an excellent institutional research environment boasting cutting-edge resources, facilities, and dynamic opportunities for collaboration. Execution of this training plan, under the guidance of expert mentors and collaborators in fields of cancer biology, chromatin biochemistry, proteomics, and genomics, will provide an invaluable foundation meant to launch a successful career as a physician-scientist cancer researcher.