Department of Molecular Biology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi-shi, Chiba 274-8510, Japan.
Department of Molecular Biology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi-shi, Chiba 274-8510, Japan.
Gene. 2021 Jun 30;787:145647. doi: 10.1016/j.gene.2021.145647. Epub 2021 Apr 15.
RecQ4, a member of the RecQ helicase family, is required for the maintenance of genome integrity. RecQ4 has been shown to promote the following two DNA double-strand break (DSB) repair pathways: non-homologous end joining (NHEJ) and homologous recombination (HR). However, its molecular function has not been fully elucidated. In the present study, we aimed to investigate the role of RecQ4 in NHEJ using Xenopus egg extracts. The N-terminal 598 amino acid region of Xenopus RecQ4 (N598), which lacks a central helicase domain and a downstream C-terminal region, was added to the extracts and its effect on the joining of DNA ends was analyzed. We found that N598 inhibited the joining of linearized DNA ends in the extracts. In addition, N598 inhibited DSB-induced chromatin binding of Ku70, which is essential for NHEJ, while the DSB-induced chromatin binding of the HR-associated proteins, replication protein A (RPA) and Rad51, increased upon the addition of N598. These results suggest that RecQ4 possibly influences the choice of the DSB repair pathway by influencing the association of the Ku heterodimer with the DNA ends.
RecQ4 是 RecQ 解旋酶家族的成员之一，对于维持基因组完整性是必需的。已经证明 RecQ4 可以促进以下两种 DNA 双链断裂 (DSB) 修复途径：非同源末端连接 (NHEJ) 和同源重组 (HR)。然而，其分子功能尚未完全阐明。在本研究中，我们旨在使用非洲爪蟾卵提取物研究 RecQ4 在 NHEJ 中的作用。在提取物中添加了缺少中央解旋酶结构域和下游 C 末端区域的非洲爪蟾 RecQ4 (N598) 的 N 端 598 个氨基酸区域，并分析其对 DNA 末端连接的影响。我们发现 N598 抑制了提取物中线性化 DNA 末端的连接。此外，N598 抑制了 DSB 诱导的 Ku70 与染色质的结合，Ku70 对于 NHEJ 是必需的，而 N598 的添加增加了与 HR 相关的蛋白质复制蛋白 A (RPA) 和 Rad51 与染色质的 DSB 诱导结合。这些结果表明 RecQ4 可能通过影响 Ku 异二聚体与 DNA 末端的结合来影响 DSB 修复途径的选择。
