Role of the ATPase domain of the Cockayne syndrome group B protein in UV induced apoptosis
Role of the ATPase domain of the Cockayne syndrome group B protein in UV induced apoptosis
复制标题
DOI：
10.1038/sj.onc.1203372
复制
发表时间：
2000-01-27
期刊：
影响因子：
8
通讯作者：
Bohr, VA
中科院分区：
文献类型：
--
作者：
Balajee, AS;DeSantis, LP;Bohr, VA
Cockayne综合征（CS）是一种常染色体隐性遗传疾病，以多种神经和发育异常为特征，CS细胞在转录偶联修复（TCR）途径中存在缺陷，该途径可从活性基因的转录链中清除DNA损伤，患有CS的个体通常不发展为癌症，但表现出神经退行性变。CS中没有癌症形成可能是由于通过自杀途径选择性消除含有DNA损伤的细胞。在这项研究中，我们评估了CSB基因在紫外线诱导的人和仓鼠细胞凋亡中的作用。仓鼠细胞系UV 61携带人CSB基因同源物的突变，我们表明，与正常细胞相比，人CS-B和仓鼠UV 61细胞在UV暴露后显示出增加的凋亡反应，UV 61细胞对凋亡的增加的敏感性通过野生型人CSB基因的转染得到补充，为了确定CSB基因的哪个功能结构域参与凋亡途径，我们构建了具有不同CSB结构域破坏的稳定细胞系，用在ATP酶基序II中高度保守的谷氨酸残基中含有点突变的人CSB cDNA稳定转染UV 61细胞，该细胞系（UV 61/pc3.1-CSBE 646 Q）显示与UV 61细胞相同的凋亡增加。相反，在CSB蛋白的N-末端的酸性结构域中含有缺失的细胞对凋亡没有影响，这表明CSB蛋白的ATP酶结构域的完整性对于防止UV诱导的凋亡途径是至关重要的。在原代人CS-B细胞中，p53蛋白的诱导和稳定似乎与它们增加的凋亡潜力相关。相反，在UV暴露后的仓鼠UV 61细胞中没有观察到p53水平或p53对mdm 2蛋白的激活的变化。这表明仓鼠细胞中CSB依赖性细胞凋亡途径的发生与p53的反式激活潜力无关。
Cockayne syndrome (CS) is a human autosomal recessive disorder characterized by many neurological and developmental abnormalities, CS cells are defective in the transcription coupled repair (TCR) pathway that removes DNA damage from the transcribed strand of active genes, The individuals suffering from CS do not generally develop cancer but show increased neurodegeneration, Two genetic complementation groups (CS-A and CS-B) have been identified, The lack of cancer formation in CS may be due to selective elimination of cells containing DNA damage by a suicidal pathway. In this study, we have evaluated the role of the CSB gene in UV induced apoptosis in human and hamster cells. The hamster cell line UV61 carries a mutation in the homolog of the human CSB gene, We show that both human CS-B and hamster UV61 cells display increased apoptotic response following UV exposure compared with normal cells, The increased sensitivity of UV61 cells to apoptosis is complemented by the transfection of the wild type human CSB gene, In order to determine which functional domain of the CSB gene participates in the apoptotic pathway, we constructed stable cell lines with different CSB domain disruptions, UV61 cells were stably transfected with the human CSB cDNA containing a point mutation in the highly conserved glutamic acid residue in ATPase motif II, This cell line (UV61/pc3.1-CSBE646Q) showed the same increased apoptosis as the UV61 cells, In contrast, cells containing a deletion in the acidic domain at the N-terminal end of the CSB protein had no effect on apoptosis, This indicates that the integrity of the ATPase domain of CSB protein is critical for preventing the UV induced apoptotic pathway, In primary human CS-B cells, the induction and stabilization of the p53 protein seems to correlate with their increased apoptotic potential, In contrast, no change in the level of either p53 or activation of mdm2 protein by p53 was observed in hamster UV61 cells after UV exposure. This suggests that the CSB dependent apoptotic pathway can occur independently of the transactivation potential of p53 in hamster cells.