Analysis of checkpoint function in the germ line.

种系检查点功能分析。

• 批准号: 7930683
• 负责人: JOANNE ENGEBRECHT
• 金额: $ 24.07万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-17 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7930683
• 关键词: Adult; Aneuploidy; Animals; Apoptosis; Apoptotic; Caenorhabditis elegans; Cell Cycle; Cell Cycle Arrest; Cells; Chromatin Structure; Chromosome Pairing; Chromosomes; Complement; Congenital Abnormality; DNA; DNA Damage; Defect; Detection; Development; Double Strand Break Repair; Down Syndrome; Ensure; Female; Frequencies; Genes; Genome; Germ Cells; Germ Lines; Haploidy; Human; Incidence; Infertility; Klinefelter' s Syndrome; Malignant Neoplasms; Meiosis; Meiotic Recombination; Mitotic; Modeling; Molecular; Molecular Genetics; Monitor; Oocytes; Parents; Pathway interactions; Phase; Pregnancy loss; Process; Production; Proliferating; Proteins; Reproduction; Signal Pathway; Signal Transduction; Somatic Cell; Spontaneous abortion; Synaptonemal Complex; System; Ultraviolet Rays; X Chromosome; base; egg; gene function; human female; insight; irradiation; male; mutant; operation; prevent; public health relevance; repaired; response; sex; sperm cell

DESCRIPTION (provided by applicant): Germ cells are specialized cells that undergo mitotic proliferation followed by meiosis and cellular differentiation to generate haploid gametes for sexual reproduction. Errors in human germ cells are quite common and result in a high frequency of spontaneous abortions and aneuploid progeny (e.g., Down, Turner and Klinefelter's Syndrome). Surprisingly, checkpoint control appears to be less efficient in the human female germ line; it has been proposed that this is one reason for the high frequency of defects associated with human female gametes. Here, we propose to take advantage of the unique structural organization of the Caenorhabditis elegans germ line, the molecular genetics of the system, and the high degree of conservation with genes and pathways in humans to determine the molecular basis for differential germ-line checkpoint function between the sexes. To tackle this important problem, we will use a multi-pronged approach that relies on the strengths of C. elegans as a model for investigating sex-specific germ-line checkpoint function. To that end, we will compare the surveillance mechanisms in operation in the female and male germ lines, and determine how males selectively sense and respond to damage in proliferating germ cells by analyzing known checkpoint mutants, examining the activation state of checkpoint proteins, and by identifying new checkpoint genes. We will determine how males prevent checkpoint-activated germ-line apoptosis and whether such absence leads to a high incidence of aneuploid gametes by monitoring the status of checkpoint and apoptotic proteins and examining the viability of progeny from reciprocal crosses when meiosis is impaired in only one of the sexes. Finally, we will determine how meiotically-induced double strand breaks are repaired on a single X chromosome without eliciting a checkpoint response by monitoring the loading and disassembly of chromosomal axis and central region components of the synaptonemal complex on the male X, probing the relationship between chromatin structure and checkpoint activation, and identifying the molecular machinery that prevents the single X from eliciting a checkpoint response. An understanding of this process in the genetically tractable worm system may provide insight into why human female meiosis has less efficient checkpoint control, contributing to the high rate of errors. These studies will also provide new and important information on general mechanisms of checkpoint control, processes in which defects are central to the developmental of human cancers. PUBLIC HEALTH RELEVANCE: Germ cells form egg and sperm for sexual reproduction. Our studies are aimed at understanding how errors arise during this process. In humans, such errors result in infertility, pregnancy loss and birth defects such as Down Syndrome.

描述（由申请人提供）：生殖细胞是经历有丝分裂增殖、随后减数分裂和细胞分化以产生用于有性生殖的单倍体配子的特殊细胞。人类生殖细胞的错误非常常见，会导致自然流产和非整倍体后代的高频率（例如唐氏综合症、特纳氏综合症和克莱费尔特氏综合症）。令人惊讶的是，检查点控制在人类女性生殖系中似乎效率较低。有人提出，这是人类雌配子缺陷高发的原因之一。在这里，我们建议利用秀丽隐杆线虫种系的独特结构组织、系统的分子遗传学以及人类基因和通路的高度保守性来确定两性之间种系检查点功能差异的分子基础。为了解决这个重要问题，我们将采用多管齐下的方法，依靠秀丽隐杆线虫的优势作为研究性别特异性种系检查点功能的模型。为此，我们将比较雌性和雄性生殖系中运行的监视机制，并通过分析已知的检查点突变体、检查检查点蛋白的激活状态以及识别新的检查点基因，确定雄性如何选择性地感知和响应增殖生殖细胞的损伤。我们将通过监测检查点和凋亡蛋白的状态，并检查当仅其中一种性别的减数分裂受损时，互交后代的生存能力，确定雄性如何防止检查点激活的种系细胞凋亡，以及这种缺失是否会导致非整倍体配子的高发生率。最后，我们将通过监测雄性X上染色体轴和联会复合体中心区域成分的加载和分解，探讨染色质结构和检查点激活之间的关系，并识别阻止单个X引发检查点反应的分子机制，确定如何在单个X染色体上修复减数分裂诱导的双链断裂而不引发检查点反应。了解遗传易处理的蠕虫系统中的这一过程可能有助于了解为什么人类雌性减数分裂检查点控制效率较低，从而导致高错误率。这些研究还将提供关于检查点控制的一般机制的新的重要信息，在检查点控制的过程中，缺陷是人类癌症发展的核心。 公共卫生相关性：生殖细胞形成卵子和精子以进行有性生殖。我们的研究旨在了解在此过程中错误是如何产生的。对于人类来说，此类错误会导致不孕、流产和唐氏综合症等出生缺陷。