Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt.
University of Science and Technology, Zewail City of Science and Technology, Giza, Egypt.
Life Sci Alliance. 2021 Aug 18;4(10). doi: 10.26508/lsa.202000966. Print 2021 Oct.
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.
核苷酸单磷酸（rNMP）掺入基因组 DNA 会对基因组完整性造成严重威胁。除了修复之外，DNA 损伤容忍机制可确保在遇到未修复的损伤时继续进行复制。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 在没有真正的核糖核苷酸切除修复途径（通过 RNase H2）的情况下耐受 rNMP 掺入的新作用。在羟基脲诱导复制应激或使用突变 DNA 聚合酶（Pol ε-Pol2-M644G）增加 rNMP 基因组负担后，Rad5 的这种作用进一步得到了强调。我们进一步证明了 Rad5 的 ATP 酶和泛素连接酶结构域在 rNMP 耐受中的重要性。这些发现表明人类 Rad5 同源物解旋酶样转录因子（HLTF）和 SNF2 组蛋白连接 PHDRING 解旋酶（SHPRH）在 rNMP 耐受中具有类似的作用，这可能会影响癌细胞对复制应激诱导治疗的反应。
