Liu Mingming, Ba Zhaoqing, Costa-Nunes Pedro, Wei Wei, Li Lanxia, Kong Fansi, Li Yan, Chai Jijie, Pontes Olga, Qi Yijun
Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China.
National Institute of Biological Sciences, Beijing 102206, China.
Plant Cell. 2017 Mar;29(3):589-599. doi: 10.1105/tpc.16.00769. Epub 2017 Feb 21.
Repair of DNA double-strand breaks (DSBs) is critical for the maintenance of genome integrity. We previously showed that DSB-induced small RNAs (diRNAs) facilitate homologous recombination-mediated DSB repair in Here, we show that INVOLVED IN DE NOVO2 (IDN2), a double-stranded RNA binding protein involved in small RNA-directed DNA methylation, is required for DSB repair in Arabidopsis. We find that IDN2 interacts with the heterotrimeric replication protein A (RPA) complex. Depletion of IDN2 or the diRNA binding ARGONAUTE2 leads to increased accumulation of RPA at DSB sites and mislocalization of the recombination factor RAD51. These findings support a model in which IDN2 interacts with RPA and facilitates the release of RPA from single-stranded DNA tails and subsequent recruitment of RAD51 at DSB sites to promote DSB repair.
DNA双链断裂（DSB）的修复对于维持基因组完整性至关重要。我们之前表明，DSB诱导的小RNA（diRNA）促进了拟南芥中同源重组介导的DSB修复。在此，我们表明，参与从头甲基化2（IDN2），一种参与小RNA指导的DNA甲基化的双链RNA结合蛋白，是拟南芥中DSB修复所必需的。我们发现IDN2与异源三聚体复制蛋白A（RPA）复合物相互作用。IDN2或与diRNA结合的AGO2的缺失导致RPA在DSB位点的积累增加以及重组因子RAD51的定位错误。这些发现支持了一个模型，即IDN2与RPA相互作用，并促进RPA从单链DNA尾巴上释放，随后在DSB位点招募RAD51以促进DSB修复。
