染色体碎裂描述了微核内错误分离的染色体的灾难性破碎。尽管微核在整个分裂间期积累 DNA 双链断裂和复制缺陷，但染色体如何发生破碎仍然没有解决。使用 CRISPR-Cas9 筛选，我们确定了范可尼贫血 (FA) 途径作为染色体碎裂驱动因素的非典型作用。 FA 途径失活可抑制有丝分裂过程中的染色体破碎，而不影响微核内与间期相关的缺陷。 FA 核心复合物对 FANCI-FANCD2 的单泛素化促进其与复制不足的微核染色体的有丝分裂接合。结构选择性的 SLX4-XPF-ERCC1 核酸内切酶随后诱导持久性 DNA 复制中间体的大规模溶核，从而刺激 POLD3 依赖性有丝分裂 DNA 合成，为破碎的片段做好准备，以便在随后的细胞周期中重新组装。值得注意的是，FA 途径诱导的染色体碎裂会产生复杂的基因组重排和染色体外 DNA，从而赋予抗癌治疗获得性耐药性。我们的研究结果证明了中央 DNA 修复机制的病理激活如何通过染色体碎裂矛盾地触发癌症基因组进化。版权所有 © 2024 Elsevier Inc. 保留所有权利。

Chromothripsis describes the catastrophic shattering of mis-segregated chromosomes trapped within micronuclei. Although micronuclei accumulate DNA double-strand breaks and replication defects throughout interphase, how chromosomes undergo shattering remains unresolved. Using CRISPR-Cas9 screens, we identify a non-canonical role of the Fanconi anemia (FA) pathway as a driver of chromothripsis. Inactivation of the FA pathway suppresses chromosome shattering during mitosis without impacting interphase-associated defects within micronuclei. Mono-ubiquitination of FANCI-FANCD2 by the FA core complex promotes its mitotic engagement with under-replicated micronuclear chromosomes. The structure-selective SLX4-XPF-ERCC1 endonuclease subsequently induces large-scale nucleolytic cleavage of persistent DNA replication intermediates, which stimulates POLD3-dependent mitotic DNA synthesis to prime shattered fragments for reassembly in the ensuing cell cycle. Notably, FA-pathway-induced chromothripsis generates complex genomic rearrangements and extrachromosomal DNA that confer acquired resistance to anti-cancer therapies. Our findings demonstrate how pathological activation of a central DNA repair mechanism paradoxically triggers cancer genome evolution through chromothripsis.Copyright © 2024 Elsevier Inc. All rights reserved.