COM1, a Factor of Alternative Non-homologous End Joining (NHEJ), Lagging Behind the Classic NHEJ Pathway in Rice Somatic Cells.
COM1, a Factor of Alternative Non-homologous End Joining (NHEJ), Lagging Behind the Classic NHEJ Pathway in Rice Somatic Cells.
复制标题
DOI：
10.1111/tpj.14715
复制
发表时间：
2020-02
期刊：
影响因子：
--
通讯作者：
Zhan Xu;Jianxiang Zhang;Xinjie Cheng;Yujie Tang;Z. Gong;M. Gu;Hengxiu Yu
中科院分区：
文献类型：
--
作者：
Zhan Xu;Jianxiang Zhang;Xinjie Cheng;Yujie Tang;Z. Gong;M. Gu;Hengxiu Yu
水稻 (Oryza sativa) COM1 在减数分裂同源重组 (HR) 中的作用已广为人知，但其在体细胞双链断裂 (DSB) 修复中的作用仍不清楚。在这里，我们发现 COM1 赋予水稻植株对化学物质博来霉素和丝裂霉素 C 引起的 DNA 损伤的耐受性，而 COM1 突变不会损害 HR 效率和 HR 因子（RAD51 和 RAD51 旁系同源物）定位到辐射诱导的 DSB。 com1-2 mre11 双突变体和 mre11 单突变体在发芽后阶段观察到类似的生长迟缓，而 COM1 与 HR 通路基因 (RAD51C) 或经典 NHEJ 通路基因 (KU70、KU80 和 LIG4) 的组合突变导致更多的表型缺陷。在 ku70 突变体中，响应 γ 辐射，COM1 正常加载到 DSB 上，但无法正确加载到 MRE11RNAi 植物和渥曼青霉素处理的野生型植物中。在非辐照条件下，野生型细胞核中因子（MRE11、COM1和LIG4）比RAD51旁系同源物（RAD51B、RAD51C和XRCC3）占据更多的DSB位点，并且ku70突变体中COM1和XRCC3的蛋白负载量增加。因此，与性母细胞中 HR 的作用完全不同，水稻 COM1 在体细胞中的替代 NHEJ 途径中特异性发挥作用，该途径基于 Mre11-Rad50-Nbs1 (MRN) 复合物并由 PI3K 样激酶促进。 NHEJ 因子（而非 HR 因子）优先加载内源 DSB，KU70 限制 COM1 和 XRCC3 在植物体细胞中的 DSB 定位。
The role of rice (Oryza sativa) COM1 in meiotic homologous recombination (HR) is well-understood, but its part in somatic double-strand break (DSB) repair remains unclear. Here, we show that COM1 confers the tolerance against DNA damages for rice plants caused by the chemicals, bleomycin and mitomycin C, while COM1 mutation did not compromise HR efficiencies and HR factors (RAD51 and RAD51 paralogs) localization to irradiation-induced DSBs. The similar retarded growth at post-germination stage were observed in com1-2 mre11 double mutant and the mre11 single mutant, while combined mutations of the COM1 with HR pathway gene (RAD51C) or classic NHEJ pathway genes (KU70, KU80, and LIG4) caused more phenotypic defects. In response to γ-irradiation, COM1 was loaded normally onto DSBs in ku70 mutant, but could not be properly loaded in MRE11RNAi plant and wortmannin-treated wild-type plant. Under non-irradiated condition, more DSB sites were occupied by the factors (MRE11, COM1, and LIG4) than RAD51 paralogs (RAD51B, RAD51C, and XRCC3) in the nucleus of wild-type, and the protein loading of COM1 and XRCC3 was increased in the ku70 mutant. Thus, quite different with its role for HR in meiocytes, rice COM1 specifically acts in an alternative NHEJ pathway in somatic cells, based on the Mre11-Rad50-Nbs1 (MRN) complex and facilitated by PI3K-like kinases. And the NHEJ factors, not the HR factors, preferentially load on the endogenous DSBs, with the KU70 restricting DSB-localization of COM1 and XRCC3 in plant somatic cells.