Human Ku70/80 associates physically with telomerase through interaction with hTERT
Human Ku70/80 associates physically with telomerase through interaction with hTERT
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DOI：
10.1074/jbc.m208542200
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发表时间：
2002-12-06
影响因子：
4.8
通讯作者：
Shay, JW
中科院分区：
文献类型：
--
作者：
Chai, WH;Ford, LP;Shay, JW
端粒长度维持是染色体稳定和基因组完整所必需的一项活动，它受端粒酶和端粒相关因子的调控。DNA修复蛋白Ku （Ku70和Ku80亚基的异源二聚体）与哺乳动物端粒有关，并有助于端粒的维持。在这里，我们在体内和体外分析了Ku与人类端粒酶的物理关联。无论是否存在dna依赖性蛋白激酶催化亚基，在肿瘤细胞和端粒酶永生化的正常细胞的提取物中，人类Ku蛋白特异性抗体都能沉淀人类端粒酶。同样的Ku抗体也在体外重组端粒酶中沉淀，表明这种关联不需要端粒DNA。此外，在端粒酶RNA （hTR）或端粒DNA缺失的情况下，Ku与体外翻译的端粒酶催化亚基（hTERT）相关。本文的研究结果首次报道了Ku与hTERT的关联，这种相互作用可能调节端粒酶到达端粒DNA末端的途径。
Telomere length maintenance, an activity essential for chromosome stability and genome integrity, is regulated by telomerase- and telomere-associated factors. The DNA repair protein Ku (a heterodimer of Ku70 and Ku80 subunits) associates with mammalian telomeres and contributes to telomere maintenance. Here, we analyzed the physical association of Ku with human telomerase both in vivo and in vitro. Antibodies specific to human Ku proteins precipitated human telomerase in extracts from tumor cells, as well as from telomerase-immortalized normal cells, regardless of the presence of DNA-dependent protein kinase catalytic subunit. The same Ku antibodies also precipitated in vitro reconstituted telomerase, suggesting that this association does not require telomeric DNA. Moreover, Ku associated with the in vitro translated catalytic subunit of telomerase (hTERT) in the absence of telomerase RNA (hTR) or telomeric DNA. The results presented here are the first to report that Ku associates with hTERT, and this interaction may function to regulate the access of telomerase to telomeric DNA ends.