PrimPol-dependent single-stranded gap formation mediates homologous recombination at bulky DNA adducts.
PrimPol-dependent single-stranded gap formation mediates homologous recombination at bulky DNA adducts.
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DOI：
10.1038/s41467-020-19570-7
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发表时间：
2020-11-17
影响因子：
16.6
通讯作者：
Petermann E
中科院分区：
文献类型：
--
作者：
Piberger AL;Bowry A;Kelly RDW;Walker AK;González-Acosta D;Bailey LJ;Doherty AJ;Méndez J;Morris JR;Bryant HE;Petermann E
RAD51介导的同源重组(HR)可以重新启动和修复停滞的复制叉，但HR也可以在绕过障碍后进行复制后修复。笨重的DNA加合物是重要的复制阻断损伤，但尚不清楚它们是在停滞的叉子上还是在正在进行的叉子后面激活HR。主要使用BPDE-DNA加合物作为模型损伤，我们发现在哺乳动物细胞中由大量加合物诱导的HR主要发生在DNA/RNA引物PrimPol形成的复制后间隙。在这些条件下，RAD51的招募不是由于叉子失速，而是发生在PrimPol重新引发以及Mre11和EXO1切除所形成的缺口中。相反，RAD51在双链断裂时加载不需要PrimPol。在体积较大的加合物中，PrimPol促进姐妹染色单体交换和遗传重组。我们的数据支持哺乳动物细胞中的HR参与复制后的缝隙修复，并确定了PrimPol在HR介导的DNA损伤耐受中的作用。块状DNA加合物是重要的复制阻断损伤。在这里，作者揭示了哺乳动物细胞中大型加合物上的同源重组涉及复制后缺口修复，并以PrimPol依赖的方式进行。
Stalled replication forks can be restarted and repaired by RAD51-mediated homologous recombination (HR), but HR can also perform post-replicative repair after bypass of the obstacle. Bulky DNA adducts are important replication-blocking lesions, but it is unknown whether they activate HR at stalled forks or behind ongoing forks. Using mainly BPDE-DNA adducts as model lesions, we show that HR induced by bulky adducts in mammalian cells predominantly occurs at post-replicative gaps formed by the DNA/RNA primase PrimPol. RAD51 recruitment under these conditions does not result from fork stalling, but rather occurs at gaps formed by PrimPol re-priming and resection by MRE11 and EXO1. In contrast, RAD51 loading at double-strand breaks does not require PrimPol. At bulky adducts, PrimPol promotes sister chromatid exchange and genetic recombination. Our data support that HR at bulky adducts in mammalian cells involves post-replicative gap repair and define a role for PrimPol in HR-mediated DNA damage tolerance. Bulky DNA adducts are important replication-blocking lesions. Here the authors reveal that homologous recombination at bulky adducts in mammalian cells involves post-replicative gap repair in a PrimPol dependent manner.