Genome instability induced by homologous recombination

项目摘要 拟议研究的总体目标是确定通过哪些途径及其机制 同源重组通过重复发生的事件导致体细胞基因组的不稳定性 DNA序列。使用萌芽酵母酿酒酵母作为模式生物，我们将定义 单个RAD51-ssDNA诱导的多重侵袭诱导重排的突变特征 丝状物与不同染色体或不同位置的重复DNA序列同时配对 单染色体。这些目标旨在建立适用的新机制和模式 关于基因组稳定性和基因组维护的中心问题。我们将建立新的突变 由同源重组引起的签名，将有助于定义这种 在人类身上发现的特征，包括癌症基因组。此外，我们的工作将有助于理解 在个体发育和发育过程中塑造基因组的主要过程的潜在机制 进化，包括非等位同源重组、插入、突变阵雨(Kataegis)、双 微小的染色体形成，以及染色体不稳定综合征，如嗜铬细胞症。 具体目标是： 1.确定多次入侵引起的基因组重排的遗传后果。多个- 侵袭诱导的重排与单链DNA和次级DNA双链相关。 搁浅的休息。我们将定义这些中间体的诱变潜力，这些中间体由最初的单个 DNA双链断裂以产生第二波重排(目标1A)、插入(目标1B)、 聚集性点突变(Aim 1C)和染色体外环形成(Aim 1D)。 2.确定影响多重入侵和全基因组同源性搜索的途径。vbl.使用 遗传终点分析的多重入侵介导的重排，我们发展了一个机制模型 防止多次入侵的质量控制。在目标2A中，我们将定义类型和位置的影响 是DSB的。在目标2B中，我们将使用物理分析来直接量化单次和多次入侵以及 DNA产品来测试我们的模型。多重入侵是全基因组同源性的敏感读数 搜索。配合我们的体检，我们在Aim 2C有独特的机会来确定 全球核结构和过程对体内全基因组同源搜索效率的影响。

Project Summary The general goal of the proposed research is to define the pathways and their mechanisms by which homologous recombination contributes to genome instability in somatic cells through events involving repeated DNA sequences. Using the budding yeast Saccharomyces cerevisiae as a model organism we will define the mutational signatures of multi-invasion-induced rearrangements, which are induced by a single Rad51-ssDNA filament simultaneously pairing with repeated DNA sequences on different chromosomes or locations on a single chromosome. The aims are designed to establish novel mechanisms and paradigms that are applicable to central questions concerning genomic stability and genome maintenance. We will establish novel mutational signatures caused by homologous recombination that will help to define the mechanism underlying such signatures found in humans, including cancer genomes. Moreover, our work will contribute to understanding the mechanisms underlying major processes that shape genomes during ontogenic development and evolution, including non-allelic homologous recombination, insertions, mutation showers (kataegis), double minute chromosome formation, and chromosome instability syndromes such as chromothripsis. The Specific Aims are: 1. Determine the genetic consequences of multi-invasion-induced genome rearrangements. Multi- invasion-induced rearrangements are associated with single-stranded DNA and secondary DNA double- stranded breaks. We will define the mutagenic potential of these intermediates induced by the initial single DNA double-strand break to generate secondary waves of rearrangements (Aim 1A), insertions (Aim 1B), clustered point mutations (Aim 1C), and extrachromosomal circle formation (Aim 1D). 2. Identify pathways that affect multi-invasions and the genome-wide search for homology. Using genetic endpoint analysis of multi-invasion-mediated rearrangements, we developed a mechanistic model of quality control that guards against multi-invasions. In Aim 2A, we will define the impact of the type and position of the DSB. In Aim 2B, we will use physical assays to directly quantify single- and multi-invasions as well as the DNA product to test our model. Multi-invasions are sensitive readouts of the genome-wide homology search. Paired with our physical assays, we have the unique opportunity in Aim 2C to determine to effect of global nuclear architecture and processes on the efficiency of the genome-wide homology search in vivo.