Ku86 is essential in human somatic cells
Ku86 is essential in human somatic cells
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DOI：
10.1073/pnas.022649699
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发表时间：
2002-01-22
影响因子：
11.1
通讯作者：
Hendrickson, EA
中科院分区：
文献类型：
--
作者：
Li, G;Nelsen, C;Hendrickson, EA
Ku 86在哺乳动物的非同源末端连接中起关键作用。在啮齿类动物中的Ku 86或Ku 70（形成DNA依赖性蛋白激酶复合物的异二聚体DNA末端结合亚基）的功能失活与生存力是相容的。相比之下，没有人类患者被描述具有Ku 86或Ku 70中的突变。这导致了这样的假设，即这些基因正在执行额外的重要作用和/或存在冗余的途径，当这些基因在人体中突变时，这些途径掩盖了这些基因的表型表达。为了解决这个问题，我们在这里描述了含有Ku 86基因座的靶向破坏的人体细胞系的构建。Ku 86杂合子的人HCT 116结肠癌细胞是单倍不足的，多倍体细胞增加，细胞增殖减少，p53水平升高，对电离辐射有轻微的超敏反应。第二个Ku 86等位基因的功能失活导致细胞的倍增时间大大减少。这些细胞只能进行有限数量的细胞分裂，然后进行凋亡。这些实验证明Ku 86基因座在人体组织培养细胞中是必需的。
Ku86 plays a key role in nonhomologous end joining in mammals. Functional inactivation in rodents of either Ku86 or Ku70, which form the heterodimeric DNA end-binding subunit of the DNA-dependent protein kinase complex, is nevertheless compatible with viability. In contrast, no human patient has been described with mutations in either Ku86 or Ku70. This has led to the hypotheses that either these genes are performing an additional essential role(s) and/or redundant pathways exist that mask the phenotypic expression of these genes when they are mutated in humans, To address this issue, we describe here the construction of human somatic cell lines containing a targeted disruption of the Ku86 locus. Human HCT116 colon cancer cells heterozygous for Ku86 were haploinsufficient with an increase in polyploid cells, a reduction in cell proliferation, elevated p53 levels, and a slight hypersensitivity to ionizing radiation. Functional inactivation of the second Ku86 allele resulted in cells with a drastically reduced doubling time. These cells were capable of undergoing only a limited number of cell divisions, after which they underwent apoptosis. These experiments demonstrate that the Ku86 locus is essential in human somatic tissue culture cells.