LOSS OF THE CATALYTIC SUBUNIT OF THE DNA-DEPENDENT PROTEIN-KINASE IN DNA DOUBLE-STRAND-BREAK-REPAIR MUTANT MAMMALIAN-CELLS
LOSS OF THE CATALYTIC SUBUNIT OF THE DNA-DEPENDENT PROTEIN-KINASE IN DNA DOUBLE-STRAND-BREAK-REPAIR MUTANT MAMMALIAN-CELLS
复制标题
DOI：
10.1073/pnas.92.8.3171
复制
发表时间：
1995-04-11
影响因子：
11.1
通讯作者：
CHEN, DJ
中科院分区：
文献类型：
--
作者：
PETERSON, SR;KURIMASA, A;CHEN, DJ
dna依赖性蛋白激酶（DNA-PK）由三个多肽组分组成：Ku-70、Ku-80和一个大约350-kDa的催化亚基（p350），编码Ku-80亚基的基因与x射线敏感组5互补基因XRCC5相同。Ku-80 cDNA的表达在5组突变细胞中恢复了DNA双链断裂（DSB）修复和V(D)J重组。Ku-80参与这些过程表明，这些突变细胞的潜在缺陷可能是DNA-PK全酶的破坏。在本报告中，我们发现p350激酶亚基在来自严重联合免疫缺陷小鼠和中国仓鼠卵巢细胞系V-3的细胞中缺失，这两种细胞在DSB修复和V(D)J重组中都存在缺陷。人类8号染色体的一个着丝粒片段可以补充酸缺陷，也可以恢复p350蛋白的表达，并恢复体外DNA-PK活性。这些数据表明，scid基因可能编码p350蛋白或调节其表达，并且与DNA-PK是dsb修复途径的关键组成部分的模型一致。
The DNA-dependent protein kinase (DNA-PK) consists of three polypeptide components: Ku-70, Ku-80, and an approximate to 350-kDa catalytic subunit (p350), The gene encoding the Ku-80 subunit is identical to the x-ray-sensitive group 5 complementing gene XRCC5. Expression of the Ku-80 cDNA rescues both DNA double-strand break (DSB) repair and V(D)J recombination in group 5 mutant cells. The involvement of Ku-80 in these processes suggests that the underlying defect in these mutant cells may be disruption of the DNA-PK holoenzyme. In this report we show that the p350 kinase subunit is deleted in cells derived from the severe combined immunodeficiency mouse and in the Chinese hamster ovary cell line V-3, both of which are defective in DSB repair and V(D)J recombination. A centromeric fragment of human chromosome 8 that complements the acid defect also restores p350 protein expression and rescues in vitro DNA-PK activity, These data suggest the scid gene may encode the p350 protein or regulate its expression and are consistent with a model whereby DNA-PK is a critical component of the DSB-repair pathway.