Investigating the factors that influence genome stability when replication forks encounter single-strand DNA breaks and protein roadblocks

DNA复制是生命繁殖的基础。它是由复杂的蛋白质机器执行的，这些机器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。在真核生物中，复制开始于细胞周期的S阶段的起始点的激发。在发射时，每个起始点都会释放一对“复制叉子”，它们从起始点向相反的方向移动。当来自相邻来源的叉子合并时，DNA复制完成。这种潜在的无缝复制起始、延长和终止模式被不同类型的单链DNA断裂(SSB)和蛋白质-DNA复合体(PDC)破坏，它们阻止复制分叉进展。复制叉子堵塞会导致复制机拆卸和叉子断裂。它还可能导致DNA复制不足，从而导致细胞分裂过程中的染色体分离问题。这些潜在的结果对基因组稳定性构成了重大威胁，通过不同方式保护、修复和重新启动受阻的分叉的途径缓解了基因组稳定性。然而，这些途径并不是没有风险的，还可能导致突变和基因组重排，这可能会促进衰老和癌症等与年龄相关的疾病。该项目的目的是确定SSB/PDC的性质和背景如何影响细胞对复制分叉阻断的反应，以及这反过来如何影响突变和基因组重排的风险。我们还将发现一些关键因素，这些因素将指导受阻的叉子沿着更安全的路线进行处理，并使汇聚在PDC的叉子得到解决。由于基因组退化被认为是老龄化过程的关键驱动因素，更好地了解其根本原因和减缓其进程的因素，最终将指导制定新的战略，以最大限度地发挥我们健康老龄化的潜力。

DNA replication is fundamental to the propagation of life. It is performed by complex protein machines, 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. In eukaryotes, replication commences with the firing of origins during S-phase of the cell cycle. Upon firing, each origin releases a pair of "replication forks" that travel in opposite directions away from their site of initiation. DNA replication is completed when forks from adjacent origins merge. This potentially seamless pattern of replication initiation, elongation and termination is disrupted by different types of single-strand DNA breaks (SSBs) and protein-DNA complexes (PDCs), which block replication fork progression. Replication fork blockage can cause the replication machine to disassemble and the fork to break. It can also cause under-replication of DNA and consequent problems with chromosome segregation during cell division. These potential outcomes pose a major threat to genome stability, which is mitigated by pathways that variously protect, repair and restart blocked forks. However, these pathways are not risk-free and can also cause mutations and genome rearrangements, which may promote ageing and age-related diseases such as cancer. The aim of this project is to determine how the cellular response to replication fork blockage is affected by the nature and context of the SSB/PDC, and how this in turn influences the risk of mutation and genome rearrangement. We will also discover key factors that direct the processing of blocked forks down safer routes and enable forks converged at PDCs to be resolved. As genome deterioration is thought to be a key driver of the ageing process, a better understanding of its root causes, and factors that slow its progress, will ultimately guide the development of new strategies to maximise our potential for healthy ageing.