Department of Molecular Biosciences, University of South Florida, Tampa, FL 33620, United States; Graduate program in Cell and Molecular Biology, University of South Florida, Tampa, FL 33620, United States.
Department of Molecular Biosciences, University of South Florida, Tampa, FL 33620, United States; Graduate program in Cell and Molecular Biology, University of South Florida, Tampa, FL 33620, United States; Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, United States.
DNA Repair (Amst). 2023 Jun;126:103488. doi: 10.1016/j.dnarep.2023.103488. Epub 2023 Mar 30.
The genome must be monitored to ensure its duplication is completed accurately to prevent genome instability. In Saccharomyces cerevisiae, the 5' to 3' DNA helicase Rrm3, a member of the conserved PIF1 family, facilitates replication fork progression through an unknown mechanism. Disruption of Rrm3 helicase activity leads to increased replication fork pausing throughout the yeast genome. Here, we show that Rrm3 contributes to replication stress tolerance in the absence of the fork reversal activity of Rad5, defined by its HIRAN domain and DNA helicase activity, but not in the absence of Rad5's ubiquitin ligase activity. The Rrm3 and Rad5 helicase activities also interact in the prevention of recombinogenic DNA lesions, and DNA lesions that accumulate in their absence need to be salvaged by a Rad59-dependent recombination pathway. Disruption of the structure-specific endonuclease Mus81 leads to accumulation of recombinogenic DNA lesions and chromosomal rearrangements in the absence of Rrm3, but not Rad5. Thus, at least two mechanisms exist to overcome fork stalling at replication barriers, defined by Rad5-mediated fork reversal and Mus81-mediated cleavage, and contribute to the maintenance of chromosome stability in the absence of Rrm3.
必须监测基因组以确保其准确复制，以防止基因组不稳定。在酿酒酵母中，5' 到 3' DNA 解旋酶 Rrm3 是保守的 PIF1 家族的成员，通过未知的机制促进复制叉的进展。破坏 Rrm3 解旋酶活性会导致整个酵母基因组中复制叉暂停增加。在这里，我们表明 Rrm3 有助于在没有 Rad5 的叉反转活性的情况下耐受复制应激，该活性由其 HIRAN 结构域和 DNA 解旋酶活性定义，但在没有 Rad5 的泛素连接酶活性的情况下则不然。Rrm3 和 Rad5 的解旋酶活性也相互作用以防止重组性 DNA 损伤，并且在它们不存在的情况下需要通过 Rad59 依赖性重组途径来挽救 DNA 损伤。破坏结构特异性内切酶 Mus81 会导致在没有 Rrm3 的情况下积累重组性 DNA 损伤和染色体易位，但没有 Rad5。因此，至少有两种机制可以克服复制障碍处的叉停滞，由 Rad5 介导的叉反转和 Mus81 介导的切割定义，并有助于在没有 Rrm3 的情况下维持染色体稳定性。
