Branzei Dana, Szakal Barnabas
IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
DNA Repair (Amst). 2016 Aug;44:68-75. doi: 10.1016/j.dnarep.2016.05.008. Epub 2016 May 16.
Replication perturbations activate DNA damage tolerance (DDT) pathways, which are crucial to promote replication completion and to prevent fork breakage, a leading cause of genome instability. One mode of DDT uses translesion synthesis polymerases, which however can also introduce mutations. The other DDT mode involves recombination-mediated mechanisms, which are generally accurate. DDT occurs prevalently postreplicatively, but in certain situations homologous recombination is needed to restart forks. Fork reversal can function to stabilize stalled forks, but may also promote error-prone outcome when used for fork restart. Recent years have witnessed important advances in our understanding of the mechanisms and DNA structures that mediate recombination-mediated damage-bypass and highlighted principles that regulate DDT pathway choice locally and temporally. In this review we summarize the current knowledge and paradoxes on recombination-mediated DDT pathways and their workings, discuss how the intermediate DNA structures may influence genome integrity, and outline key open questions for future research.
复制扰动会激活DNA损伤耐受(DDT)途径,这对于促进复制完成和防止叉状结构断裂至关重要,而叉状结构断裂是基因组不稳定的主要原因。DDT的一种模式使用跨损伤合成聚合酶,然而这种酶也可能引入突变。另一种DDT模式涉及重组介导的机制,这种机制通常是准确的。DDT普遍发生在复制后,但在某些情况下需要同源重组来重新启动叉状结构。叉状结构逆转可起到稳定停滞叉状结构的作用,但用于叉状结构重新启动时也可能促进易出错的结果。近年来,我们对介导重组介导的损伤旁路的机制和DNA结构的理解取得了重要进展,并突出了在局部和时间上调节DDT途径选择的原则。在这篇综述中,我们总结了关于重组介导的DDT途径及其作用机制的当前知识和矛盾之处,讨论了中间DNA结构如何影响基因组完整性,并概述了未来研究的关键开放性问题。