Molecular Basis of Centromere Specification and Inheritance

着丝粒规格和遗传的分子基础

• 批准号: 10334471
• 负责人: Fei Li
• 金额: $ 39.22万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10334471
• 关键词: Address; Affect; Aneuploidy; Animal Model; Biochemistry; Cell Cycle; Cell division; Cells; Cellular Structures; Centromere; Chromatin; Chromosome Segregation; Chromosomes; Cytology; DNA biosynthesis; Daughter; Development; Diagnosis; Disease; Down Syndrome; Ensure; Epigenetic Process; Eukaryota; Eukaryotic Cell; Fission Yeast; Foundations; Functional disorder; Gene Silencing; Genetic; Genome; Genomics; Goals; Heterochromatin; Histone H3; Human; Kinetochores; Knowledge; Lead; Light; Link; Malignant Neoplasms; Meiosis; Mitosis; Molecular; Normal Cell; Process; Regulation; Role; Ubiquitin-mediated Proteolysis Pathway; Variant; centromere protein A; chromosome number abnormality; daughter cell; design; epigenetic regulation; human disease; insight; interdisciplinary approach; prevent; segregation; structural biology

PROJECT SUMMARY/ABSTRACT A fundamental but poorly understood process in eukaryotic cells is how cells structure their genomes into distinct functional domains. This project addresses this gap in knowledge by studying the centromere, a specific chromatin domain found in all eukaryotes. This stably propagated locus guides the assembly of kinetochores to ensure proper segregation of chromosomes during mitosis and meiosis. Mis-regulation of centromeres adversely affects chromosome segregation resulting in aneuploidy, a condition found in more than 90% of all cancers. Aneuploidy contributes to the development of many diseases, such as cancer and Down syndrome. The goal of this project is to understand the molecular mechanisms underlying the specification and inheritance of centromeres. In most eukaryotes, centromeres are epigenetically governed by the centromere-specific histone H3 variant, CENP-A. CENP-A partially replaces canonical histone H3 at centromeres, and provides the foundation for the assembly of kinetochores. Centromeres are usually embedded in epigenetically distinct heterochromatin, the transcriptionally silenced chromatin domain. Assembly of CENP-A at centromeres is cell cycle-regulated. Parental CENP-A is partitioned equally among daughter centromeres following DNA replication, whereas loading of newly synthesized CENP-A to centromeres is uncoupled from DNA replication. How CENP-A chromatin at centromeres is assembled throughout the cell cycle remains poorly understood. Mislocalization of CENP-A to non-centromeric regions has a devastating impact on chromosome segregation, and has been linked to a variety of cancers. Ubiquitin- mediated proteolysis of CENP-A is a conserved mechanism to prevent CENP-A mislocalization. But how non- centromeric regions are protected from CENP-A mis-incorporation in normal cells is largely unexplored. In addition, CENP-A in centromeres is interspersed with the canonical histone H3. The histone H3 within centromeres is actually vital for proper assembly of CENP-A chromatin. How CENP-A and H3 levels are properly balanced in centromeres is unknown. We propose to use fission yeast (Schizosaccharomyces pombe) to address these outstanding questions. Fission yeast is a simple eukaryotic model organism with many aspects of centromere regulation conserved with humans. It is particularly suited to an interdisciplinary approach that includes genetics, genomics, cytology, biochemistry, and structural biology. We propose to: 1) define the mechanisms underlying cell cycle-dependent CENP-A assembly at centromeres, 2) determine how formation of ectopic CENP-A chromatin is prevented, 3) identify regulatory mechanism for how CENP-A and histone H3 levels are balanced at centromeres. Our study also provides important new insights into the role of heterochromatin in centromere function. Given that epigenetic regulation in fission yeast is conserved, our studies will shed light on the processes governing chromosome segregation in human cells, and contribute to a better understanding of human diseases resulting from centromere misregulation.

项目摘要/摘要 真核细胞中的基本但知之甚少的过程是细胞如何将其基因组构造到 不同的功能域。该项目通过研究Centromere来解决这一知识的差距 在所有真核生物中发现的特定染色质结构域。这个稳定的繁殖基因座指南 动力学以确保有丝分裂和减数分裂过程中染色体的适当分离。错误调节 中心粒对染色体隔离产生不利影响，导致非整倍性，这种情况在更多的情况下发现 所有癌症中的90％。非整倍性有助于许多疾病的发展，例如癌症和 唐氏综合症。该项目的目的是了解该项目的分子机制 中心粒的规范和继承。在大多数真核生物中，centromeres在表观遗传学上受 Centromere特异性组蛋白H3变体CENP-A。 CENP-A部分替代了典型的组蛋白H3 centromeres，并为组装动物学奠定了基础。通常是中心 嵌入在表观遗传上不同的异染色质中，转录沉默的染色质结构域。 CENP-A在中心粒中的组装是细胞周期调节的。父母CENP-A在 DNA复制后的女子centromeres，而新合成的CENP-A则加载到 Centromeres与DNA复制无耦合。 cenp-a染色质如何组装 在整个细胞周期中，人们的了解仍然很少。 CENP-A的错误定位到非中心区域 对染色体分离有毁灭性的影响，并与各种癌症有关。泛素 - CENP-A的介导蛋白水解是预防CENP-A错误定位的保守机制。但是多么非 在正常细胞中保护着丝粒区域免受CENP-A错误结构的保护。在 此外，中心粒中的CENP-A与规范组蛋白H3散布在一起。内部组蛋白H3 中心粒实际上对于正确组装CENP-A染色质至关重要。 CENP-A和H3水平如何 中心粒中适当平衡是未知的。我们建议使用裂变酵母（schizosacchomyces pombe） 解决这些出色的问题。裂变酵母是一种简单的真核模型生物，有许多 对人类保守的丝粒调节的各个方面。它特别适合跨学科 包括遗传学，基因组学，细胞学，生物化学和结构生物学的方法。我们建议：1） 定义依赖细胞周期的CENP-A组件的机制，2）确定如何确定 预防异位CENP-A染色质的形成，3）确定CENP-A和 组蛋白H3水平在丝粒处平衡。我们的研究还提供了重要的新见解 丝粒功能中的异染色质。鉴于裂变酵母中的表观遗传调节是保守的，我们 研究将阐明人类细胞中染色体隔离的过程，并有助于 更好地理解着丝粒不利的人类疾病。