DNA double-strand breaks (DSBs) are highly toxic lesions that threaten genome integrity and cell survival. To avoid harmful repercussions of DSBs, a wide variety of DNA repair factors are recruited to execute DSB repair. Previously, we demonstrated that RBM6 splicing factor facilitates homologous recombination (HR) of DSB by regulating alternative splicing-coupled nonstop-decay of the HR protein APBB1/Fe65. Here, we describe a splicing-independent function of RBM6 in promoting HR repair of DSBs. We show that RBM6 is recruited to DSB sites and PARP1 activity indirectly regulates RBM6 recruitment to DNA breakage sites. Deletion mapping analysis revealed a region containing five glycine residues within the G-patch domain that regulates RBM6 accumulation at DNA damage sites. We further ascertain that RBM6 interacts with Rad51, and this interaction is attenuated in RBM6 mutant lacking the G-patch domain (RBM6del(G-patch)). Consequently, RBM6del(G-patch) cells exhibit reduced levels of Rad51 foci after ionizing radiation. In addition, while RBM6 deletion mutant lacking the G-patch domain has no detectable effect on the expression levels of its splicing targets Fe65 and Eya2, it fails to restore the integrity of HR. Altogether, our results suggest that RBM6 recruitment to DSB promotes HR repair, irrespective of its splicing activity.HIGHLIGHTSPARP1 activity indirectly regulates RBM6 recruitment to DNA damage sites.Five glycine residues within the G-patch domain of RBM6 are critical for its recruitment to DNA damage sites, but dispensable for its splicing activity.RBM6 G-patch domain fosters its interaction with Rad51 and promotes Rad51 foci formation following irradiation.RBM6 recruitment to DSB sites underpins HR repair.

中文翻译：

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将 RBM6 募集到 DNA 双链断裂促进同源重组修复。

DNA 双链断裂 (DSB) 是威胁基因组完整性和细胞存活的剧毒损伤。为了避免 DSB 的有害影响，广泛的 DNA 修复因子被招募来执行 DSB 修复。以前，我们证明 RBM6 剪接因子通过调节 HR 蛋白 APBB1/Fe65 的可变剪接耦合不间断衰变来促进 DSB 的同源重组 (HR)。在这里，我们描述了 RBM6 在促进 DSB 的 HR 修复中的独立剪接功能。我们表明 RBM6 被招募到 DSB 站点，PARP1 活动间接调节 RBM6 招募到 DNA 断裂站点。删除作图分析揭示了 G-patch 域中包含五个甘氨酸残基的区域，该区域调节 DNA 损伤位点的 RBM6 积累。我们进一步确定 RBM6 与 Rad51 相互作用，并且这种相互作用在缺乏 G-patch 结构域的 RBM6 突变体 (RBM6del(G-patch)) 中减弱。因此，RBM6del（G 补丁）细胞在电离辐射后表现出 Rad51 病灶水平降低。此外，虽然缺少 G-patch 结构域的 RBM6 缺失突变体对其剪接靶标 Fe65 和 Eya2 的表达水平没有可检测的影响，但它无法恢复 HR 的完整性。总而言之，我们的结果表明，RBM6 募集到 DSB 会促进 HR 修复，无论其剪接活动如何。HIGHLIGHTSPARP1 活动间接调节 RBM6 募集到 DNA 损伤位点。RBM6 G-patch 域内的五个甘氨酸残基对其募集到 DNA 损伤至关重要位点，但因其剪接活性而可有可无。RBM6 G-patch 结构域促进其与 Rad51 的相互作用，并促进辐射后 Rad51 病灶的形成。