Ribonucleoside monophosphate (rNMP) incorporation in genomic DNA poses a significant threat to genomic integrity. In addition to repair, DNA damage tolerance mechanisms ensure replication progression upon encountering unrepaired lesions. One player in the tolerance mechanism is Rad5, which is an E3 ubiquitin ligase and helicase. Here, we report a new role for yeast Rad5 in tolerating rNMP incorporation, in the absence of the bona fide ribonucleotide excision repair pathway via RNase H2. This role of Rad5 is further highlighted after replication stress induced by hydroxyurea or by increasing rNMP genomic burden using a mutant DNA polymerase (Pol ε - Pol2-M644G). We further demonstrate the importance of the ATPase and ubiquitin ligase domains of Rad5 in rNMP tolerance. These findings suggest a similar role for the human Rad5 homologues helicase-like transcription factor (HLTF) and SNF2 Histone Linker PHD RING Helicase (SHPRH) in rNMP tolerance, which may impact the response of cancer cells to replication stress-inducing therapeutics.

中文翻译：

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Rad5 在核糖核苷一磷酸 (rNMP) 耐受中的作用。

核糖核苷一磷酸 (rNMP) 掺入基因组 DNA 对基因组完整性构成重大威胁。除了修复之外，DNA 损伤耐受机制确保在遇到未修复的损伤时复制进程。耐受机制中的一个参与者是 Rad5，它是一种 E3 泛素连接酶和解旋酶。在这里，我们报告了酵母 Rad5 在没有通过 RNase H2 的真正核糖核苷酸切除修复途径的情况下，在耐受 rNMP 掺入中的新作用。在羟基脲诱导的复制应激或通过使用突变 DNA 聚合酶 (Pol ε - Pol2-M644G) 增加 rNMP 基因组负荷后，Rad5 的这一作用进一步突出。我们进一步证明了 Rad5 的 ATP 酶和泛素连接酶结构域在 rNMP 耐受性中的重要性。