How CHAF1B maintains cell state by repressing transcription of fate genes

CHAF1B 如何通过抑制命运基因的转录来维持细胞状态

• 批准号: 10271523
• 负责人: Andrew Volk
• 金额: $ 39.75万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-15 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10271523
• 关键词: Affect; Automobile Driving; Binding; Cell Cycle; Cell Differentiation process; Cell division; Cells; Chromatin; Chromatin Modeling; Complex; DNA; DNA replication fork; Differentiated Gene; Disease; Enhancers; Epigenetic Process; Floods; Gene Activation; Gene Expression; Genes; Genetic Diseases; Genetic Transcription; Goals; Histone H3; Homeostasis; Knowledge; Link; Malignant Neoplasms; Modeling; Mutate; Pancytopenia; Phenotype; Replication-Associated Process; Reporting; Role; S Phase; Tissues; Transcription Repressor; Transcriptional Regulation; Up-Regulation; chromatin assembly factor I; chromatin protein; gene repression; human disease; novel; promoter; protein complex; recruit; stem cells; tool; transcription factor

PROJECT SUMMARY: Comprehensive regulation of transcription is a major mechanism by which immature cells functionally determine their identity. The epigenetic factors responsible for this transcriptional regulatory activity are some of the most potent, and most commonly mutated, factors implicated in tissue homeostasis and disease. We understand the role of many epigenetic factors responsible for activating transcription, but we have a limited understanding of the factors that repress transcription associated with differentiation. Additionally, we know many of the epigenetic transcriptional regulators present on the chromatin before and after replication, but we have a limited understanding of how these factors interact during replication. The relative lack of understanding of how the replication machinery regulates transcription associated with cell identity is a key knowledge gap in the field of epigenetics. Our studies suggest that the Chromatin Assembly Factor 1 (CAF1) complex, functioning in its canonical role of replication-linked chromatin assembly, is the critical factor responsible for directly regulating fate-specific transcription during replication. CAF1 is a heterotrimeric protein complex responsible for facilitating histone H3/H4 heterodimer assembly at the replication fork during the S phase of cell cycle. Our lab focuses on the functional contributions of CAF1 through studying its p60 subunit: Chromatin Assembly Factor 1B (CHAF1B). We are using CHAF1B as a model for CAF1 function because of the abundance of tools and expertise we have generated to study CHAF1B and the overwhelming evidence that readouts of CHAF1B and the CAF1 complex are functionally identical. CHAF1B is highly expressed in uncommitted stem cells, and its expression decreases as cells differentiate. We recently reported that CHAF1B directly binds chromatin at promoters and enhancers of differentiation genes, repressing their expression by blocking transcription factor binding. Depletion of CHAF1B in independent models led to massive upregulation of gene activation caused by transcription factors flooding regions of chromatin previously occupied by CHAF1B. This led to our hypothesis: CHAF1B is a master regulator of cell identity through a novel role as transcriptional repressor of fate genes in immature cells. Our long-term goal is to understand how cells regulate transcription associated with cell fate throughout differentiation. Our short-term goal is to understand how the chromatin assembly machinery affects transcriptional repression of fate genes in immature cells. In this proposal we will study the functional roles of the factors responsible for CHAF1B direct binding to chromatin on transcription and phenotype (Focus 1), and the contributions of the DNA/protein complexes recruited by CHAF1B to the chromatin on transcription and phenotype (Focus 2). Discoveries about CHAF1B, the CAF1 complex, and the larger DNA/protein chromatin landscape it promotes, have the potential for driving sweeping changes in the way we understand functional epigenetics and treat disease.

项目摘要： 转录的综合调节是一种主要机制 确定他们的身份。负责这种转录调节活性的表观遗传因素是一些 最有效，最常见的突变因素与组织稳态和疾病有关。我们 了解许多负责激活转录的表观遗传因素的作用，但我们的作用有限 了解压抑与分化相关的转录因素。另外，我们知道 复制之前和之后的染色质上存在许多表观遗传转录调节剂，但我们 对这些因素在复制过程中的相互作用有限。相对缺乏理解 关于如何调节与细胞身份相关的转录的复制机制是关键知识差距 在表观遗传学领域。我们的研究表明，染色质组装因子1（CAF1）复合物， 在复制连锁染色质组装的规范作用中发挥作用，是负责的关键因素 在复制过程中直接调节命运特异性转录。 CAF1是一种杂点蛋白复合物，负责促进组蛋白H3/H4异二聚体 在细胞周期的S阶段复制叉处的组装。我们的实验室专注于功能贡献 通过研究其p60亚基的CAF1：染色质组装因子1b（CHAF1B）。我们正在使用CHAF1B 作为CAF1功能的模型，由于我们已经生成的大量工具和专业知识 CHAF1B以及CHAF1B和CAF1复合物的读数的压倒性证据在功能上是 完全相同的。 CHAF1B在不合同的干细胞中高度表达，其表达随着细胞而降低 区分。我们最近报告说，CHAF1B直接在启动子和增强子上结合染色质 分化基因，通过阻止转录因子结合来抑制其表达。 CHAF1B的耗竭 在独立模型中，导致转录因子洪水引起的基因激活的大量上调 先前由CHAF1B占据的染色质区域。这导致了我们的假设：CHAF1B是大师 细胞身份的调节剂是通过作为未成熟细胞中命运基因的转录抑制剂的新作用来调节的。 我们的长期目标是了解细胞如何调节与细胞命运相关的转录 在整个区分中。我们的短期目标是了解染色质组装机械如何 影响未成熟细胞中命运基因的转录抑制。在此提案中，我们将研究功能 负责CHAF1B直接结合染色质和表型的因素的作用（聚焦 1），以及CHAF1B募集的DNA/蛋白质复合物的贡献 和表型（焦点2）。有关CHAF1B，CAF1复合物和较大DNA/蛋白的发现 它所促进的染色质景观，有可能在我们理解的方式上推动全面变化 功能性表观遗传学和治疗疾病。