Molecular Mechanisms of Chromosome Segregation in Yeast

酵母染色体分离的分子机制

• 批准号: 8130735
• 负责人: JENNIFER L GERTON
• 金额: $ 29.8万
• 依托单位: STOWERS INSTITUTE FOR MEDICAL RESEARCH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8130735
• 关键词: Amino Acid Sequence; Aneuploidy; Animal Model; Attention; Biochemical; Biological; Biological Models; Cancer Etiology; Cell Cycle; Cell Nucleus; Cells; Centromere; Chromatin; Chromosome Segregation; Chromosomes; Cis-Acting Sequence; Colorectal Cancer; Complex; DNA; Defect; Deposition; Down Syndrome; Drosophila genus; Elements; Ensure; Eukaryotic Cell; Genome; Goals; Growth; Health; Histone H3; Histones; Homologous Gene; Human; In Vitro; Karyopherins; Kinetochores; Maintenance; Malignant Neoplasms; Mass Spectrum Analysis; Meiosis; Microtubules; Mitotic; Modeling; Molecular; Monitor; Nuclear; Nuclear Import; Nucleosomes; Organism; Pathway interactions; Phenotype; Ploidies; Proteins; Role; Saccharomyces cerevisiae; Saccharomycetales; Sister Chromatid; Spontaneous abortion; Structure; Testing; Variant; Yeasts; base; centromere protein A; daughter cell; developmental disease; fly; genetic manipulation; in vitro testing; in vivo; man; mutant; novel; overexpression; protein structure; reconstitution; research study; segregation

DESCRIPTION (provided by applicant): All organisms have mechanisms to ensure that cells produced from mitotic and meiotic divisions contain the proper number of chromosomes. The cell monitors that chromosomes are copied exactly once and then distributed correctly to daughter cells. This is critical since errors result in an incomplete chromosome complement which is highly correlated with cancer and causes spontaneous miscarriage, Downs, and other developmental disorders in humans. Our long term goal is to understand the molecular mechanisms that contribute to the fidelity of chromosome distribution. Many chromosome segregation mechanisms are conserved from budding yeast to man. Due to the ease of genetic manipulations in budding yeast, we use S. cerevisiae as our model organism. In particular, this proposal will explore the molecular mechanisms of chromosome segregation with particular attention to centromeres and kinetochores. Centromeres are cis acting sequences on chromosomes that are required for their correct segregation. Although centromere sequence is highly variable between organisms, centromeres are universally marked by a histone H3 variant, known as Cse4/CENP-A. This histone variant is incorporated into nucleosomes with centromere sequence which is critical to direct the formation of the kinetochore, a multi-protein structure essential for microtubule attachment and therefore chromosome segregation. The goal of this proposal is to understand in molecular detail how Cse4/CENP-A- containing nucleosomes are established and maintained in the genome. In particular we will characterize the role of a novel Cse4-associated factor on Cse4-deposition, kinetochore function and chromosome segregation. Our ultimate goal is to reconstruct centromeric chromatin and the inner kinetochore in vitro. These types of experiments will help us build the first detailed molecular understanding of centromeric chromatin and inner kinetochore formation in any organism. Our studies will help us evaluate current models for the function of centromeres and kinetochores in chromosome segregation, and may help elucidate the etiology of cancer and new avenues for therapy. PUBLIC HEALTH RELEVANCE Each cell in the body must maintain the correct number of chromosomes. When chromosomes are not accurately divided between cells, aneuploidy results, which is the state of having too many or too few chromosomes. Aneuploidy is highly correlated with cancer and causes spontaneous miscarriage and developmental disorders such as Downs syndrome. In particular, the topic of this proposal, Cse4/CENP-A, is a protein that is essential for the formation of centromeres and kinetochores, features of chromosomes that are required for their accurate segregation. Cse4/CENP-A has been shown to be overexpressed and mistargeted in human primary colorectal cancers [1]. An associated protein, CENP-H, induces aneuploidy when overexpressed in human cells [2]. Overexpression of CID, the fly homolog of CENP-A, promotes formation of ectopic centromeres and multicentric chromosomes which causes chromosome missegregation, aneuploidy, and growth defects [3]. These results demonstrate that Cse4/CENP-A significantly contributes to genome maintenance. A better understanding of the molecular requirements for localization of Cse4/CENP-A to centromeres and its participation in kinetochore function is crucial to our understanding of basic mechanisms that contribute to accurate chromosome segregation. 1. Tomonaga, T., et al., Overexpression and mistargeting of centromere protein-A in human primary colorectal cancer. Cancer Res, 2003. 63: p. 3511-6. 2. Tomonaga, T., et al., Centromere protein H is up-regulated in primary human colorectal cancer and its overexpression induces aneuploidy. Cancer Res, 2005. 65: p. 4683-9. 3. Heun, P., et al., Mislocalization of the Drosophila centromere-specific histone CID promotes formation of functional ectopic kinetochores. Dev Cell, 2006. 10: p. 303-15.

描述（由申请人提供）：所有生物都有机制，以确保由有丝分裂和减数分裂分裂产生的细胞包含适当数量的染色体。细胞监测染色体准确复制一次，然后正确分布到子细胞中。这很关键，因为错误会导致不完全的染色体补体，这与癌症高度相关，并导致人类自发流产，唐斯和其他发育障碍。我们的长期目标是了解有助于染色体分布的保真度的分子机制。从萌芽的酵母到人，许多染色体隔离机制都是保守的。由于散发酵母中的遗传操作易于性，我们使用酿酒酵母作为模型生物体。特别是，该建议将探索染色体隔离的分子机制，并特别注意丝粒和动脉化合物。中心粒是其正确分离所需的染色体上的顺式作用序列。尽管中心仪序列在生物体之间是高度变化的，但共晶粒以组蛋白H3变体（称为CSE4/CENP-A）普遍标记。该组蛋白变体被纳入具有丝粒序列的核小体中，这对于指导Kinetochore的形成至关重要，这是一种用于微管附着和因此染色体隔离所必需的多蛋白结构。该提议的目的是用分子详细了解CSE4/CENP-A-含有核小体的核心小体和维持在基因组中。特别是，我们将表征新型CSE4相关因子在CSE4沉积，动力学功能和染色体分离中的作用。我们的最终目标是在体外重建开心粒染色质和内部动力学。这些类型的实验将有助于我们建立对任何生物体中丝粒染色质和内部动物学形成的第一个详细的分子理解。我们的研究将有助于我们评估当前模型的丝粒和动力学在染色体分离中的功能，并可能有助于阐明癌症的病因和新的治疗途径。公共卫生相关性的每个细胞必须保持正确的染色体数量。当染色体不准确地分配在细胞之间时，非整倍性结果，这是染色体太多或太少的状态。非整倍性与癌症高度相关，并引起自发流产和发育障碍，例如唐斯综合征。特别是，该提案的主题CSE4/CENP-A是一种蛋白质，对于形成丝粒和动物学的蛋白质是必不可少的，这是其准确隔离所需的染色体的特征。 CSE4/CENP-A已显示出在人类主要结直肠癌中过表达和误入[1]。当人类细胞过表达时，相关蛋白CENP-H会诱导非整倍性[2]。 CID（CENP-A的Fly同源物）的过表达促进了引起染色体错误凝结，非整倍性和生长缺陷的异位丝粒和多中心染色体的形成[3]。这些结果表明，CSE4/CENP-A显着有助于基因组维持。更好地理解CSE4/CENP-A定位对cencentromeres及其参与动力学功能的分子要求至关重要，这对于我们对有助于准确染色体隔离的基本机制的理解至关重要。 1。Tomonaga，T。等人，在人类原发性结直肠癌中Centromere蛋白A的过表达和误射。 Cancer Res，2003。63：p。 3511-6。 2。Tomonaga，T。等人，Centromere蛋白H在原发性人结直肠癌及其过表达中被上调。 Cancer Res，2005。65：p。 4683-9。 3。Heun，P。等人，果蝇中心粒特异性组蛋白CID的错误定位促进了功能异位动物学的形成。 Dev Cell，2006。10：p。 303-15。