Feng Sumin, Zhao Yichao, Xu Yixi, Ning Shaokai, Huo Wei, Hou Mei, Gao Ge, Ji Jianguo, Guo Rong, Xu Dongyi
From the State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.
From the State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
J Biol Chem. 2016 Oct 14;291(42):21956-21962. doi: 10.1074/jbc.C116.747758. Epub 2016 Sep 6.
The replication protein A (RPA) complex binds single-stranded DNA generated at stalled replication forks and recruits other DNA repair proteins to promote recovery of these forks. Here, we identify Ewing tumor-associated antigen 1 (ETAA1), which has been linked to susceptibility to pancreatic cancer, as a new repair protein that is recruited to stalled forks by RPA. We demonstrate that ETAA1 interacts with RPA through two regions, each of which resembles two previously identified RPA-binding domains, RPA70N-binding motif and RPA32C-binding motif, respectively. In response to replication stress, ETAA1 is recruited to stalled forks where it colocalizes with RPA, and this recruitment is diminished when RPA is depleted. Notably, inactivation of the ETAA1 gene increases the collapse level of the stalled replication forks and decreases the recovery efficiency of these forks. Moreover, epistasis analysis shows that ETAA1 stabilizes stalled replication forks in an ataxia telangiectasia and Rad3-related protein (ATR)-independent manner. Thus, our results reveal that ETAA1 is a novel RPA-interacting protein that promotes restart of stalled replication forks.
复制蛋白A（RPA）复合物结合在停滞的复制叉处产生的单链DNA，并招募其他DNA修复蛋白以促进这些复制叉的恢复。在此，我们鉴定出与胰腺癌易感性相关的尤因肿瘤相关抗原1（ETAA1），它是一种新的修复蛋白，可被RPA招募至停滞的复制叉。我们证明ETAA1通过两个区域与RPA相互作用，这两个区域分别类似于先前鉴定的两个RPA结合结构域，即RPA70N结合基序和RPA32C结合基序。响应复制应激时，ETAA1被招募至停滞的复制叉，与RPA共定位，而当RPA缺失时，这种招募作用减弱。值得注意的是，ETAA1基因的失活会增加停滞复制叉的崩溃水平，并降低这些复制叉的恢复效率。此外，上位性分析表明，ETAA1以一种与共济失调毛细血管扩张症和Rad3相关蛋白（ATR）无关的方式稳定停滞的复制叉。因此，我们的结果揭示ETAA1是一种新型的与RPA相互作用的蛋白，可促进停滞复制叉的重新启动。
