RAD51形成核蛋白丝来促进同源重组、复制叉反转和叉保护。许多因素调控这些丝的稳定性，不当的调控导致基因组不稳定性和最终的疾病，包括癌症。RADX是一个单链DNA结合蛋白，调节RAD51丝的稳定性。在这里，我们利用CRISPR依赖的碱基编辑筛选技术，在RADX上铺砌突变位点，以界定RADX功能所需的模体。我们发现了RADX的功能分离突变体，它们能够结合DNA和RAD51，但减少了刺激其ATP水解活性的能力。表达这些RADX突变体的细胞在染色质上积累RAD51，表现出复制缺陷，生长减慢，积累DNA损伤，并对DNA损伤和复制应激敏感。这些结果表明，RADX必须促进RAD51的ATP周转，以调控DNA复制过程中的RAD51和基因组稳定性。版权所有 © 2023 Elsevier Ltd. 保留所有权利。

RAD51 forms nucleoprotein filaments to promote homologous recombination, replication fork reversal, and fork protection. Numerous factors regulate the stability of these filaments and improper regulation leads to genomic instability and ultimately disease including cancer. RADX is a single stranded DNA binding protein that modulates RAD51 filament stability. Here, we utilize a CRISPR-dependent base editing screen to tile mutations across RADX to delineate motifs required for RADX function. We identified separation of function mutants of RADX that bind DNA and RAD51 but have a reduced ability to stimulate its ATP hydrolysis activity. Cells expressing these RADX mutants accumulate RAD51 on chromatin, exhibit replication defects, have reduced growth, accumulate DNA damage, and are hypersensitive to DNA damage and replication stress. These results indicate that RADX must promote RAD51 ATP turnover to regulate RAD51 and genome stability during DNA replication.Copyright © 2023 Elsevier Ltd. All rights reserved.