Human DNA polymerase iota protects cells against oxidative stress
Human DNA polymerase iota protects cells against oxidative stress
复制标题
DOI：
10.1038/emboj.2008.210
复制
发表时间：
2008-11-05
期刊：
影响因子：
11.4
通讯作者：
Kannouche, Patricia
中科院分区：
文献类型：
--
作者：
Petta, Tirzah Braz;Nakajima, Satoshi;Kannouche, Patricia
人类DNA聚合酶iota （poli）是特殊聚合酶y家族的独特成员，具有5'脱氧核糖磷酸（dRP）裂解酶活性。尽管poli在高等真核生物中保存良好，但其在哺乳动物细胞中的作用尚不清楚。为了研究poli在人类细胞中的生物学重要性，我们生成了稳定下调poli（MRC5-poli(KD)）的成纤维细胞，并检测了它们对几种dna损伤剂的反应。我们发现下调poli的细胞系对过氧化氢（H2O2）或甲萘醌诱导的DNA损伤表现出超敏反应，但对乙基甲烷磺酸钠（EMS）、UVC或UVA则不敏感。有趣的是，下调poli的细胞提取物显示碱基切除修复（BER）活性降低。此外，在H2O2处理细胞后，poli与染色质结合，并与BER因子XRCC1相互作用。最后，绿色荧光蛋白标记的poli在活细胞中DNA氧化损伤位点积累。这种招募部分是由其dRP裂解酶结构域和泛素结合结构域介导的。这些数据揭示了人类蛋白质在保护细胞免受氧化损伤方面的新作用。
Human DNA polymerase iota (poli) is a unique member of the Y-family of specialised polymerases that displays a 5'deoxyribose phosphate (dRP) lyase activity. Although poli is well conserved in higher eukaryotes, its role in mammalian cells remains unclear. To investigate the biological importance of poli in human cells, we generated fibroblasts stably downregulating poli (MRC5-poli(KD)) and examined their response to several types of DNA-damaging agents. We show that cell lines downregulating poli exhibit hypersensitivity to DNA damage induced by hydrogen peroxide (H2O2) or menadione but not to ethyl-methane sulphonate ( EMS), UVC or UVA. Interestingly, extracts from cells downregulating poli show reduced base excision repair (BER) activity. In addition, poli binds to chromatin after treatment of cells with H2O2 and interacts with the BER factor XRCC1. Finally, green fluorescent protein-tagged poli accumulates at the sites of oxidative DNA damage in living cells. This recruitment is partially mediated by its dRP lyase domain and ubiquitin-binding domains. These data reveal a novel role of human poli in protecting cells from oxidative damage.