Single-strand interruptions in replicating chromosomes cause double-strand breaks
Single-strand interruptions in replicating chromosomes cause double-strand breaks
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DOI：
10.1073/pnas.131009198
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发表时间：
2001-07-17
影响因子：
11.1
通讯作者：
Kuzminov, A
中科院分区：
文献类型：
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作者：
Kuzminov, A
复制依赖性染色体断裂表明，复制叉偶尔会碰到模板DNA中的切口并崩溃，产生双链末端。为了模拟体内复制叉崩溃，我构建了携带M13噬菌体切口位点的噬菌体λ染色体，并用这些底物感染大肠杆菌细胞，产生M13切口酶。我在从这些细胞中纯化的λ DNA的切口部位检测到双链断裂。双链断裂取决于（i）切口位点的存在;（ii）切口酶的产生;和（iii）含切口染色体的复制。复制叉在模板DNA缺口处的崩溃解释了多种现象，包括DNA拓扑异构酶抑制剂对真核细胞的杀伤和重组缺陷脊椎动物细胞系的灭活。
Replication-dependent chromosomal breakage suggests that replication forks occasionally run into nicks in template DNA and collapse, generating double-strand ends. To model replication fork collapse in vivo, I constructed phage lambda chromosomes carrying the nicking site of M13 bacteriophage and infected with these substrates Escherichia coli cells, producing M13 nicking enzyme. I detected double-strand breaks at the nicking sites in lambda DNA purified from these cells. The double-strand breakage depends on (i) the presence of the nicking site; (ii) the production of the nicking enzyme; and (iii) replication of the nick-containing chromosome. Replication fork collapse at nicks in template DNA explains diverse phenomena, including eukaryotic cell killing by DNA topoisomerase inhibitors and inviability of recombination-deficient Vertebrate cell lines.