Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
Mol Cell. 2010 Nov 24;40(4):645-57. doi: 10.1016/j.molcel.2010.10.022. Epub 2010 Nov 4.
Replication stress involving collision of replisomes with camptothecin (CPT)-stabilized DNA-Topoisomerase I adducts activates an ATR-dependent pathway to promote repair by homologous recombination. To identify human genes that protect cells from such replication stress, we performed a genome-wide CPT sensitivity screen. Among numerous candidate genes are two previously unstudied proteins: the ankyrin repeat protein NFKBIL2 and C6ORF167 (MMS22L), distantly related to yeast replication stress regulator Mms22p. MMS22L and NFKBIL2 interact with each other and with FACT (facilitator of chromatin transcription) and MCM (minichromosome maintenance) complexes. Cells depleted of NFKBIL2 or MMS22L are sensitive to DNA-damaging agents, load phosphorylated RPA onto chromatin in a CTIP-dependent manner, activate the ATR/ATRIP-CHK1 and double-strand break repair signaling pathways, and are defective in HR. This study identifies MMS22L-NFKBIL2 as components of the replication stress control pathway and provides a resource for discovery of additional components of this pathway.
复制压力涉及复制体与喜树碱（CPT）稳定的 DNA-拓扑异构酶 I 加合物的碰撞，激活 ATR 依赖性途径，促进同源重组修复。为了鉴定能使细胞免受这种复制压力的人类基因，我们进行了全基因组 CPT 敏感性筛选。在众多候选基因中，有两个以前未研究过的蛋白质：锚蛋白重复蛋白 NFKBIL2 和 C6ORF167（MMS22L），它们与酵母复制应激调节剂 Mms22p 有较远的关系。MMS22L 和 NFKBIL2 相互作用，与 FACT（染色质转录的辅助因子）和 MCM（微染色体维持）复合物相互作用。NFKBIL2 或 MMS22L 耗尽的细胞对 DNA 损伤剂敏感，以 CTIP 依赖性方式将磷酸化的 RPA 加载到染色质上，激活 ATR/ATRIP-CHK1 和双链断裂修复信号通路，并在 HR 中缺陷。这项研究确定了 MMS22L-NFKBIL2 是复制应激控制途径的组成部分，并为发现该途径的其他成分提供了资源。
