Elucidating the molecular mechanisms of structure-selective endonucleases in DNA repair and genome stability

DNA 是每个生物体的重要组成部分，它提供了生命的蓝图，并且是每个细胞的生物过程所必需的。在正常细胞生长过程中，这种遗传信息必须准确复制并传播到两个子细胞。矛盾的是，DNA 非常容易受到自然发生的物质（例如代谢副产物）和环境中的物质（例如紫外线辐射、致癌化学物质）的损害。如果不修复，受损的 DNA 可能会引发突变、染色体重排和基因组不稳定。为了抵消基因毒性剂的有害影响，细胞含有复杂的 DNA 修复网络，可保护基因组完整性并确保正常的细胞功能。了解支撑这些重要细胞通路的复杂机制是研究 DNA 修复和基因组稳定性基本生物过程的科学家的主要目标。大多数 DNA 修复途径需要结构选择性核酸内切酶 (SSE) 的作用，SSE 是一种分子剪刀，可以去除 DNA 修复（和正常细胞生长）过程中形成的潜在有毒 DNA 结构。未能去除这些结构会损害染色体稳定性。然而，DNA 切割为无差别修复打开了大门，可以促进基因重排，强调了控制 SSE 活性和防止不受控制的 DNA 切割的调控机制的重要性。保守的 SSE SLX1-SLX4、MUS81-EME1 和 XPF-ERCC1 是大多数真核生物中 DNA 重组和修复所必需的。 SLX4 蛋白为 SMX 三核酸酶复合物提供支架，该复合物是通过与 SLX1、MUS81-EME1 和 XPF-ERCC1 相互作用形成的。 SLX4 与其他几种基因组稳定性蛋白相互作用，从而形成了一种流行的模型，即 SLX4 为组装多功能大分子复合物提供了枢纽，从而协调不同的蛋白质-DNA 事务。有关这些复合体的结构、功能和调节的关键问题仍有待解决。我的研究将阐明大分子 SLX4 复合物的细胞作用、调节和生化机制。这些信息将为理解这些复合物如何发挥作用并调节基因组稳定性提供一个机制框架。我的研究还将为 DNA 重组和修复提供基本的新见解，这两者都是重要的细胞过程。我的研究为加拿大人带来了许多切实的好处，包括高素质人才的培训、研究能力的发展和知识的进步。我的研究将提升加拿大作为 DNA 修复和基因组稳定性领域研究创新和卓越中心的认可度，从而通过招募和培训世界一流的科学家来刺激经济和社会增长。

An essential component of every living organism is DNA, which provides the blueprint for life and is required for the biological processes in each and every cell. During normal cell growth, this genetic information must be accurately replicated and propagated to two daughter cells. Paradoxically, DNA is highly susceptible to damage by agents that occur naturally (e.g. metabolic by-products) and in the environment (e.g. ultraviolet radiation, carcinogenic chemicals). If left unrepaired, damaged DNA can trigger mutations, chromosomal rearrangements and genome instability. To counteract the deleterious effects of genotoxic agents, cells contain sophisticated DNA repair networks that safeguard genome integrity and ensure proper cell function. Understanding the intricate mechanisms that underpin these essential cellular pathways is a major goal of scientists that study the basic biological processes of DNA repair and genome stability. Most DNA repair pathways require the actions of structure-selective endonucleases (SSEs), which are molecular scissors that remove potentially toxic DNA structures that form during DNA repair (and normal cell growth). The failure to remove these structures compromises chromosome stability. Nevertheless, DNA cleavage opens the door for indiscriminate repair that can fuel genetic rearrangements, emphasizing the importance of regulatory mechanisms to control the activity of SSEs and prevent uncontrolled DNA cleavage.The conserved SSEs SLX1-SLX4, MUS81-EME1 and XPF-ERCC1 are required for DNA recombination and repair in most eukaryotes. The SLX4 protein provides a scaffold for the SMX tri-nuclease complex, formed by interactions with SLX1, MUS81-EME1 and XPF-ERCC1. SLX4 interacts with several other genome stability proteins, leading to the prevailing model that SLX4 provides a hub for the assembly of versatile macromolecular complexes that orchestrate diverse protein-DNA transactions. Key questions about the structure, function and regulation of these complexes remain to be addressed. My research will elucidate the cellular roles, regulation and biochemical mechanisms of macromolecular SLX4 complexes. This information will provide a mechanistic framework for understanding how these complexes function and mediate genome stability. My studies will also provide fundamental new insights into DNA recombination and repair, both of which are essential cellular processes. My research has numerous tangible benefits for Canadians, including the training of high quality personnel, development of research capacity, and knowledge advancement. My studies will elevate Canada's recognition as a hub for research innovation and excellence in the fields of DNA repair and genome stability, thereby stimulating economic and societal growth through the recruitment and training of world-class scientists.