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Understanding spontaneous mitotic crossover by single-cell multi-omics

通过单细胞多组学了解自发有丝分裂交叉

基本信息

批准号：
10799260
负责人：
Yi Yin
金额：
$ 6.69万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2026-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10799260
关键词：
Cells Mitotic Yin multiple omics

项目摘要

PROJECT SUMMARY/ABSTRACT Homologous recombination (HR) is important for repairing DNA double strand breaks (DSB), and thus is an essential process in embryonic development, meiosis and suppressing tumorigenesis. HR can also be a doubleedged sword: unrepaired breaks lead to cell death; errors by HR, particularly the crossover type, can cause extensive genome rearrangements. While the biochemical process of HR in the repair of an induced DSB has been elucidated by various methods, two critical gaps remain regarding spontaneous HR: 1) the lesions driving spontaneous mitotic HR (e.g. in addition to DSBs, template switching in replication initiated by single-strand nicks can also promote HR); and 2) HR partner choice that determines whether HR is error-free or not. The two gaps are inter-related as HR partner choice could depend on the types of initiating lesions. What determines whether HR is error-free or not is a fundamental question of what governs genome integrity. A maior technical roadblock is the lack of scalable, genome-wide tools for studying rare spontaneous HR events in many mutants. To scale YJ2. genome-wide HR mapping efforts, I developed sci-L3, which enables linear amplification of single-cell genomes that scales to 1 M cells, enabling generating hundreds of single-cell global HR maps per mutant for thousands of mutants. Moreover, genetic assays require detecting "scars" in the genome as traces of repair (e.g. in cancer mutational signature studies), which miss 99% of error-free HR between identical sister chromatids. There is thus a critical need for unbiased global assays that detect both mutational and error-free HR. I recently addressed this gap by developing sci-L3-Strand-seq as the first scalable mapping tool for HR between identical sister chromatids. Our central vision is to determine how spontaneous mitotic crossovers cause genome rearrangements by scalable single-cell assays. In Area1, we will use sci-L3 to explore the full mutant space in hybrid yeast diploids. By generating HR maps in all the single mutants in a pooled manner (160 single-cell HR maps/mutant for 6,000 mutants), we can simultaneously test and generate thousands of hypotheses regarding different lesions and pathways that drive different types of genome instability events genome-wide. In Area2, we focus on a deciding factor for whether HR is error-free or not: HR partner choice of allelic sister chromatid, allelic homolog and non-allelic repeats. With sci-L3-Strand-seq, we propose to map all the seven classes of crossover outcomes in two systems: mammalian cell lines and mouse embryos. In cell lines, we will investigate genomewide distributions of both error-free and mutational HR outcomes in the wild-type as well as hundreds of perturbations of HR-related genes to determine factors affecting HR partner choice including (epi)genomic contexts, 3D genome organization and HR gene knockdown. We will also develop in vivo sci-L3-Strand-seq/RNA co-assay to dissect cell-type variation in HR partner choice in mouse embryos. In sum, this proposal pursues cost-effective, massively parallel and genome-wide mapping of mitotic crossover outcomes as functions of genetic perturbations and cell types by developing and applying advanced single-cell multi-omics tools.

项目总结/摘要同源重组（HR）对于修复DNA双链断裂（DSB）是重要的，并且因此是一种有效的方法。胚胎发育、减数分裂和抑制肿瘤发生的重要过程。人力资源也可以是一把双刃剑剑：未修复的断裂导致细胞死亡; HR的错误，特别是交叉类型，可能导致广泛的基因组重排虽然HR在诱导DSB修复中的生化过程通过各种方法阐明，关于自发性HR仍存在两个关键差距：1）自发有丝分裂HR（例如，除DSB外，复制中由单链切口引发的模板转换也可以促进人力资源）;和2）人力资源合作伙伴的选择，决定了人力资源是否是无差错的。的两个间隙是相互关联的，因为HR伴侣的选择可能取决于起始病变的类型。是什么决定了 HR是否无误是一个决定基因组完整性的基本问题。一个主要的技术障碍缺乏可扩展的全基因组工具来研究许多突变体中罕见的自发HR事件。按比例 YJ2.在全基因组HR作图工作中，我开发了sci-L3，它能够线性扩增单细胞基因组可扩展到100万个细胞，能够为每个突变体生成数百个单细胞全局HR图谱，成千上万的变种人此外，基因测定需要检测基因组中的“疤痕”作为修复的痕迹（例如，在癌症突变特征研究中），其错过了相同姐妹染色单体之间99%的无错误HR。因此，迫切需要无偏倚的全球检测方法，以检测突变和无错误的HR。通过开发sci-L3-Strand-seq作为第一个可扩展的HR映射工具，姐妹染色单体我们的中心愿景是确定自发的有丝分裂交叉如何导致基因组通过可扩展的单细胞测定来检测重排。在Area 1中，我们将使用sci-L3来探索完整的突变空间在杂交酵母二倍体中。通过以合并的方式在所有单突变体中生成HR图谱（160个单细胞HR 地图/突变体为6,000突变），我们可以同时测试和生成数千个假设，不同的病变和途径，驱动不同类型的基因组不稳定性事件全基因组。在区域2中，我们关注HR是否无差错的决定因素：HR伴侣选择等位基因姐妹染色单体，等位基因同源物和非等位重复。使用sci-L3-Strand-seq，我们建议映射所有七类交叉两个系统的结果：哺乳动物细胞系和小鼠胚胎。在细胞系中，我们将研究全基因组在野生型以及数百个突变型中，无错误和突变HR结果的分布 HR相关基因的干扰，以确定影响HR伴侣选择的因素，包括（epi）基因组上下文、3D基因组组织和HR基因敲除。我们还将开发体内sci-L3-Strand-seq/RNA 共测定以剖析小鼠胚胎中HR伴侣选择中的细胞类型变化。总而言之，这项建议力求有丝分裂交叉结果的成本效益，大规模平行和全基因组作图，通过开发和应用先进的单细胞多组学工具，