Elucidating the Rad51-independent pathway of recombination-dependent replication

在细胞分裂之前，它必须首先复制它的遗传物质，以便每个新的子细胞都能获得一个副本。实现这一壮举的DNA复制过程依赖于被称为复制体的复杂的多蛋白质机器，这些复制体在被称为复制起点的染色体位置组装到DNA上。这些机器解开DNA双螺旋，形成“叉形”结构，复制发生在叉形结构上。在细胞周期中，沿着每条染色体的多个起始点“起火”，每个起始点都释放出一对“复制叉子”，它们以相反的方向远离它们的起始点。当来自相邻来源的叉子合并时，DNA复制完成。即使是一对叉子未能合并，也会导致一个未复制的DNA区域，这可能导致DNA断裂，并最终导致导致癌症等疾病的基因突变。DNA损伤和许多结合染色体DNA的蛋白质，通过物理上阻碍复制叉的进展，威胁到复制的成功完成。当复制叉遇到这样的障碍时，它可能会经历一个称为叉状崩溃的过程，在这个过程中，它的复制体部分或完全从DNA上分离出来。为了帮助确保在细胞周期中成功完成DNA复制，真核细胞使用两种替代的酶途径来修复和重新启动复制叉子，复制叉子在与屏障碰撞后坍塌。这个项目的目标是了解这些重新启动途径是如何工作的，重点是两者中最不被了解的，它们被认为与促进癌细胞存活有关。我们将确定该途径的组成部分，并研究它们如何发挥作用。为了实现这些目标，我们将利用一个简单的真核生物模型的遗传可控性。然而，将要研究的生物学的基本方面是高度保守的，因此，我们的发现将为指导未来的人类细胞研究提供一个有价值的范例。最终，我们的工作将有助于更好地理解复制重新启动--这一知识将对指导新型癌症疗法的开发至关重要。

Before a cell can divide, it must first replicate its genetic material so that each new daughter cell can receive a copy. The DNA replication process that achieves this feat depends on complex multi-protein machines called replisomes, which are assembled onto DNA at chromosomal sites known as replication origins. These machines unwind the DNA double helix to form "fork" structures, at which the copying occurs. During the cell cycle, multiple origins along every chromosome "fire", each releasing a pair of "replication forks" that travel in opposite directions away from their origin. DNA replication is completed when forks from adjacent origins merge. The failure of even a single pair of forks to merge results in a region of unreplicated DNA that can lead to DNA breakage, and ultimately genetic mutations that cause diseases such as cancer. DNA lesions, and the many proteins that bind chromosomal DNA, threaten successful completion of replication by physically impeding the progress of the replication fork. When a replication fork encounters such a barrier, it can undergo a process termed fork collapse in which its replisome partially or completely dissociates from the DNA. To help ensure the successful completion of DNA replication during the cell cycle, eukaryotic cells use two alternative enzymatic pathways to repair and restart replication forks that collapse following collision with a barrier. The goal of this project is to understand how these restart pathways work, focusing on the least understood of the two, which has been implicated in promoting cancer cell survival. We will identify the components of the pathway and study how they function. To achieve these objectives, we will exploit the genetic tractability of a simple model eukaryote. However, the fundamental aspects of biology that will be studied are highly conserved and, therefore, our discoveries will provide a valuable paradigm to guide future research in human cells. Ultimately, our work will contribute to a greater understanding of replication restart - knowledge that will be vital for guiding the development of novel cancer therapies.