Mechanisms of programmed chromosome breakage

程序性染色体断裂的机制

基本信息

批准号：
10552369
负责人：
Andreas Hochwagen
金额：
$ 51.86万
依托单位：
NEW YORK UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-02-01 至 2028-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10552369
关键词：
Architecture Cell Cycle Progression Cell physiology Cells Chromosome Breakage Chromosome abnormality Chromosomes Congenital Abnormality Copy Number Polymorphism DNA DNA Double Strand Break DNA Repair DNA copy number Defect Development Disease Environment Eukaryota Fertility Gene Dosage Genes Genetic Genetic Variation Genome Genomic Instability Genomics Germ Cells Germ Lines Goals Health Human Cell Line Infertility Laboratories Length Lesion Life Cycle Stages Location Loss of Heterozygosity Malignant Neoplasms Measures Meiosis Meiotic Recombination Mental disorders Molecular Molecular Biology Organism Process Research Ribosomal DNA Risk Role Saccharomyces cerevisiae Syndrome Testing Time Work Yeasts cancer predisposition developmental disease experimental study genetic variant genome integrity genome-wide genomic locus high risk insight neuronal cell body novel phosphoproteomics programs repaired surveillance network

项目摘要

Program Summary/Abstract The overall goal of this research is to understand how organisms safely break their own DNA. DNA double- strand breaks (DSBs) are highly hazardous lesions whose improper repair can cause loss of heterozygosity and copy-number variations, leading to numerous psychiatric and developmental disorders, as well as cancers. Despite these risks, most eukaryotes introduce programmed DSBs into their genomes at one or more points in their life cycle. These breaks occur in the soma and the germ line and function to create genetic diversity, remove unwanted DNA, and support adaptation to changing environments. Cells go to great lengths to keep programmed DSBs safe. They control the location and timing of DSBs, promote correct repair-template choice, and use surveillance mechanisms to coordinate DSB formation with other cellular processes, including cell-cycle progression. Defects in any of these layers of control leave organisms with a higher risk of genome instability, and thus provide key insights into the genome instability associated with cancers and the chromosomal abnormalities that lead to birth defects and infertility. To investigate safe DSB formation, the proposed work focuses on two highly conserved instances of developmentally induced DNA breakage: (1) meiotic recombination, which involves hundreds of DSBs per meiotic germ cell, and (2) programmed copy-number changes in the ribosomal DNA (rDNA), the most highly expressed gene locus in eukaryotes. The proposed work uses genetics, molecular biology, and genomics to investigate these processes. Most of the work is conducted in the yeast Saccharomyces cerevisiae, but conservation of rDNA copy-number control is also tested in human cell lines. To investigate meiotic DSBs, research over the next 5 years will build on results of a phospho-proteomics screen to dissect the surveillance network that coordinates many meiotic processes with DSB formation. Experiments will also define the role of chromosome architecture in making DSB hotspots hot, and a genome- wide approach will be developed to measure meiotic repair-template choice across the genome. To analyze copy-number dynamics in the rDNA, research will focus on the mechanisms that drive re- expansion of critically short rDNA clusters and investigate the role of a novel DNA repair intermediate in this process. In addition, the proposed work will investigate the spreading of genetic variants among repeats of an rDNA cluster over evolutionary time scales and upon selection in the laboratory. Together, these analyses will provide fundamental insights into the dynamics of developmentally induced DSBs, open avenues for understanding how these endogenous processes contribute to genomic plasticity in health and disease.

计划摘要/摘要这项研究的总体目标是了解生物体如何安全地破坏自己的 DNA。 DNA双链断裂（DSB）是高度危险的损伤，修复不当可能导致杂合性丧失和拷贝数变异，导致许多精神和发育障碍以及癌症。尽管存在这些风险，大多数真核生物还是在基因组中的一个或多个点将编程的 DSB 引入到它们的基因组中。他们的生命周期。这些断裂发生在体细胞和种系中，并起到创造遗传多样性的作用，去除不需要的 DNA，并支持适应不断变化的环境。细胞竭尽全力保护已编程 DSB 的安全。它们控制 DSB 的位置和时间，促进正确的修复模板选择，并使用监视机制来协调 DSB 的形成其他细胞过程，包括细胞周期进程。这些控制层中任何一个的缺陷都会导致具有较高基因组不稳定性风险的生物体，从而提供对基因组不稳定性的重要见解与癌症和导致出生缺陷和不孕不育的染色体异常有关。为了研究 DSB 的安全形成，拟议的工作重点关注两个高度保守的 DSB 实例发育诱导的 DNA 断裂：（1）减数分裂重组，每个减数分裂涉及数百个 DSB 减数分裂生殖细胞，以及 (2) 核糖体 DNA (rDNA) 中的程序化拷贝数变化，这是最重要的真核生物中表达的基因座。拟议的工作利用遗传学、分子生物学和基因组学来研究这些过程。大部分工作是在酿酒酵母中进行的，但是 rDNA 拷贝数控制的保守性也在人类细胞系中进行了测试。为了研究减数分裂 DSB，未来 5 年的研究将以磷酸蛋白质组学的结果为基础筛选来剖析协调许多减数分裂过程与 DSB 形成的监视网络。实验还将定义染色体结构在 DSB 热点和基因组热点中的作用。将开发广泛的方法来测量整个基因组减数分裂修复模板的选择。为了分析 rDNA 中的拷贝数动态，研究将集中于驱动重新复制的机制。扩展极短的 rDNA 簇并研究新型 DNA 修复中间体在此过程中的作用过程。此外，拟议的工作将调查遗传变异在重复序列中的传播 rDNA 簇在进化时间尺度上和实验室选择后形成。总之，这些分析将为发育诱发的动态提供基本见解。 DSB 为理解这些内源过程如何促进基因组可塑性开辟了途径健康和疾病。