Profound synthetic lethality between SMARCAL1 and FANCM (CRISPR screen). Profound synthetic lethality between SMARCAL1 and FANCM (CRISPR screen)

DNA replication stress is a threat to genome integrity. The large SNF2-family of ATPases participates in preventing and mitigating DNA replication stress by employing their ATP-driven motor to remodel DNA or DNA-bound proteins. To understand the contribution of these ATPases in genome maintenance, we undertook CRISPR-based synthetic lethality screens with three SNF2-type ATPases: SMARCAL1, ZRANB3 and HLTF. Here we show that SMARCAL1 displays a profound synthetic lethal interaction with FANCM, another ATP-dependent translocase involved in DNA replication and genome stability. Their combined loss causes severe genome instability that we link to chromosome breakage at loci enriched in simple repeats, which are known to challenge replication fork progression. Our findings illuminate a critical genetic buffering mechanism that provides an essential function for maintaining genome integrity. Overall design: Synthetic lethal interaction analysis using data from large-scale genomic CRISPR screens in RPE1-hTERT TP53-/- PACKO Cas9 cell

DNA复制应激（DNA replication stress）对基因组完整性（genome integrity）构成威胁。大型SNF2家族ATP酶（SNF2-family ATPases）可借助ATP驱动的分子马达重塑DNA或DNA结合蛋白，参与预防并缓解DNA复制应激。为明确这类ATP酶在基因组维持中的作用，我们针对SMARCAL1、ZRANB3与HLTF这三种SNF2型ATP酶，开展了基于CRISPR的合成致死筛选（CRISPR-based synthetic lethality screens）。本研究发现，SMARCAL1与另一种参与DNA复制及基因组稳定的ATP依赖移位酶（ATP-dependent translocase）FANCM存在显著的合成致死相互作用。二者联合缺失会引发严重的基因组不稳定，我们将该表型与富集简单重复序列的位点处的染色体断裂相关联——这类序列已知会阻碍复制叉的行进。本研究揭示了一种关键的遗传缓冲机制，该机制在维持基因组完整性过程中发挥必需功能。实验设计概述：利用在RPE1-hTERT TP53⁻/⁻ PACKO Cas9细胞中开展的大规模基因组CRISPR筛选数据进行合成致死相互作用分析。