A Molecular View of Chromosome Recombination & Segregation in Eukaryotic Meiosis

染色体重组的分子视角

基本信息

批准号：
8975783
负责人：
Kevin Daniel Corbett
金额：
$ 30.95万
依托单位：
LUDWIG INSTITUTE FOR CANCER RES LTD
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-12-10 至 2017-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8975783
关键词：
Accounting Address Adopted Aneuploidy Architecture Area Binding Biochemical Biological Assay Cell division Cells Child Chromosome Segregation Chromosome Structures Chromosomes Chromosomes, Human, Pair 21 Complex Crystallography Defect Dissection Down Syndrome Electron Microscopy Embryo Engineering Ensure Equilibrium Event Evolution Failure Genetic Genetic Recombination Geometry Germ Cells Head Homologous Gene Human In Vitro Individual Infertility Kinetochores Link Mediating Meiosis Meiotic Recombination Mental Retardation Microtubules Molecular Molecular Conformation Molecular Structure Monitor Mutation Nature Negative Staining Oocytes Organism Peptides Phosphotransferases Point Mutation Pregnancy Prevalence Process Property Protein Engineering Proteins Public Health Recombinant DNA Reproduction Role Saccharomyces cerevisiae Set protein Signal Transduction Sister Spontaneous abortion Staging Structure Synaptonemal Complex Techniques Testing Trisomy Work Yeast Model System crosslink design developmental disease dimer fertility improvement in vivo mutant offspring programs protein complex protein protein interaction protein structure public health relevance reconstitution segregation self assembly stoichiometry three dimensional structure

项目摘要

DESCRIPTION (provided by applicant): PROJECT SUMMARY Meiosis is a specialized cell division program that gives rise to gametes in sexually reproducing organisms. The first stage of meiosis, called meiosis I, uniquely involves the association, programmed recombination, and eventual segregation of homologous chromosomes. While this process is well understood from a genetic and cytological standpoint, our understanding of how the meiosis-specific cellular machinery is able to organize and manipulate meiotic chromosomes in 3D space to mediate their proper segregation remains a mystery. This area of study is significant, as errors in meiosis I chromosome segregation account for the vast majority of aneuploidies, extra or missing chromosomes in offspring, that occur in over half of human oocytes and 5-10% of clinically recognized pregnancies. As such, aneuploidy is the leading genetic cause of miscarriage and of mental retardation (e.g. Down syndrome, caused by trisomy of chromosome 21). The underlying causes of chromosome segregation errors in meiosis I are not well understood, and further progress toward identifying these causes will require a detailed understanding of the molecular mechanisms of meiosis-specific chromosome segregation machinery. Here, we propose to study three sets of meiotic chromosome-associated proteins that are critical for different aspects of chromosomes' organization and physical manipulation in meiosis I. Our approach combines in vitro reconstitution of purified proteins and complexes, 3D structural analysis of these complexes, and targeted genetic assays to test mutants designed to disrupt specific aspects of these proteins' structures and interactions. We will first study the S. cerevisiae monopolin complex, which binds chromosomes' kinetochores in meiosis I and modifies their attachments to spindle microtubules, to enable the proper orientation and segregation of homologous chromosomes. We will determine the architecture of the monopolin complex, and use engineered protein constructs in genetic assays to test whether it directly cross-links sister kinetochores to mediate their attachment to a single microtubule. Next, we will study the conserved chromosome-associated protein Hop1, a component of the proteinaceous "axis" about which each chromosome is organized. We will examine the roles of Hop1's conserved HORMA domain, a signaling domain shared with the spindle checkpoint protein Mad2, in regulating inter-homolog meiotic recombination, and in a meiosis-specific checkpoint monitoring recombination. Finally, we will study the synaptonemal complex, an essential polymeric assembly that links homologs together during meiotic recombination. As very little is known about the architecture of this complex or its functions, we will study the domain structure, protein-protein interactions, and self-assembly determinants of the key S. cerevisiae synaptonemal complex protein Zip1. Combined, this work will begin to provide a more accurate picture of the macromolecular structures and interactions underlying homologous chromosome recombination and segregation in meiosis I.

描述（由申请人提供）：项目摘要减数分裂是一项专门的细胞部门计划，可引起性生殖生物的配子。减数分裂的第一阶段称为减数分裂I，独特涉及同源染色体的关联，编程重组和最终隔离。尽管从遗传和细胞学的角度可以很好地理解这个过程，但我们对减数分裂特异性细胞机械如何在3D空间中组织和操纵减数分裂染色体以介导其适当的隔离仍然是一个谜。这一研究领域很重要，因为减数分裂I染色体隔离的错误占了绝大多数的非整倍性，后代的额外或缺失的染色体，这些染色体发生在人类超过一半的人类卵母细胞中，而临床认可的妊娠中有5-10％。因此，非整倍性是流产和智力低下的主要遗传学原因（例如，唐氏综合症，由染色体21的三体疾病引起）。染色体隔离误差的根本原因我对我不太了解，而识别这些原因的进一步进展将需要详细了解减数分裂特异性染色体隔离机制的分子机制。在这里，我们建议研究三组减数分裂染色体相关的蛋白质，这些蛋白对于减数分裂I的染色体组织的不同方面至关重要。我们将首先研究酿酒酵母垄断复合蛋白复合物，该复合物结合了减数分裂I中的染色体动力学，并修饰它们对纺锤体微管的附着，以实现同源染色体的适当取向和分离。我们将确定垄断络合物的结构，并在遗传测定中使用工程蛋白质构建体来测试它是否直接跨链接姐妹动物学来介导它们的附着在单个微管上。接下来，我们将研究保守的染色体相关蛋白Hop1，这是蛋白质“轴”的组成部分，每个染色体都组织起来。我们将研究Hop1保守的Horma结构域的作用，这是一个与纺锤体检查点MAD2共享的信号域，在调节同胞间减数分裂重组以及减数分裂特异性检查点监测重组中的作用。最后，我们将研究突发型复合体，这是一种必不可少的聚合物组件，在减数分裂重组过程中将同源物连接在一起。对于这种复合物或其功能的结构知之甚少，我们将研究域结构，蛋白质 - 蛋白质相互作用以及关键的酿酒酵母突发核复合物蛋白Zip1的自组装决定因素。合并后，这项工作将开始提供更准确的图景，描述了大量分子的同源染色体重组和减数分裂I的隔离。