Chk1-deficient tumour cells are viable but exhibit multiple checkpoint and survival defects
Chk1-deficient tumour cells are viable but exhibit multiple checkpoint and survival defects
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DOI：
10.1093/emboj/cdg060
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发表时间：
2003-02-03
期刊：
影响因子：
11.4
通讯作者：
Gillespie, DAF
中科院分区：
文献类型：
--
作者：
Zachos, G;Rainey, MD;Gillespie, DAF
保守的蛋白激酶Chk 1被认为在异常DNA结构的检查点反应中起重要作用;然而，Chk 1缺陷胚胎细胞的致死性使多细胞动物中Chk 1功能的遗传分析复杂化。我们已经使用基因靶向来消除体细胞DT 40 B淋巴瘤细胞中的Chk 1功能。我们发现Chk 1缺陷的DT 40细胞是活的，但不能响应于电离辐射而停滞在G（2）/M，并且对电离辐射的杀伤非常敏感。当DNA聚合酶被抑制时，Chk 1缺陷细胞也不能维持可行的复制叉或抑制无效的起点发射，导致不完全的基因组复制和从复制停滞释放后细胞存活减少。然而，与胚胎细胞相反，当DNA合成被抑制时，Chk 1不需要延迟有丝分裂。因此，Chk 1是体细胞DT 40细胞中正常细胞分裂的关键，但对于DNA损伤诱导的G2/M期阻滞和复制检查点反应的子集是必不可少的。此外，Chk 1依赖性过程在DNA结构或代谢扰动后促进肿瘤细胞存活。
The conserved protein kinase Chk1 is believed to play an important role in checkpoint responses to aberrant DNA structures; however, genetic analysis of Chk1 functions in metazoans is complicated by lethality of Chk1-deficient embryonic cells. We have used gene targeting to eliminate Chk1 function in somatic DT40 B-lymphoma cells. We find that Chk1-deficient DT40 cells are viable, but fail to arrest in G(2)/M in response to and are hypersensitive to killing by ionizing radiation. Chk1-deficient cells also fail to maintain viable replication forks or suppress futile origin firing when DNA polyrnerase is inhibited, leading to incomplete genome duplication and diminished cell survival after release from replication arrest. In contrast to embryonic cells, however, Chk1 is not required to delay mitosis when DNA synthesis is inhibited. Thus, Chk1 is dispensable for normal cell division in somatic DT40 cells but is essential for DNA damage-induced G2/M arrest and a subset of replication checkpoint responses. Furthermore, Chk1-dependent processes promote tumour cell survival after perturbations of DNA structure or metabolism.