Three homologs are all required for efficient repair of spontaneous DNA damage in Deinococcus radiodurans
Three homologs are all required for efficient repair of spontaneous DNA damage in Deinococcus radiodurans
复制标题
有效修复耐辐射奇球菌自发性 DNA 损伤需要三个同源物
DOI：
10.1007/s00792-012-0447-y
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发表时间：
2012-05-01
期刊：
影响因子：
2.9
通讯作者：
Hua, Yuejin
中科院分区：
文献类型：
--
作者：
Hua, Xiaoting;Xu, Xin;Hua, Yuejin
是一种能在极端的DNA损伤中生存下来的细菌。为了了解核酸内切酶III(Nth)在氧化修复和突变中的作用，我们构建了单、双和三个突变体。突变体的IR抗性和H_2O_2抗性与野生型无显著差异。我们使用/Rif(R)系统从突变率和突变谱方面对这些菌株进行了表征。突变体MK1(a-(3))的Rif(R)频率是野生型的两倍。ME3的三个突变体的突变频率是野生型的34.4倍，突变率是野生型的13.8倍。所有菌株都显示了特定的突变热点。在碱基替换(G：C-&Gt；A：T)时，各单突变体的自发突变频率均高于野生型。双突变体和三突变体的突变反应进一步增强。ME3有较高的突变率和突变反应，提示这三个同源物在内源性DNA氧化修复中具有不重叠和重叠的底物谱。
is a bacterium that can survive extreme DNA damage. To understand the role of endonuclease III (Nth) in oxidative repair and mutagenesis, we constructed single, double and triple mutants. The mutants showed no significant difference with wild type in both IR resistance and H2O2 resistance. We characterized these strains with regard to mutation rates and mutation spectrum using the /Rif(r) system. The Rif(r) frequency of mutant MK1 (a-(3)) was twofold higher than that of wild type. The triple mutant of (ME3)generated a mutation frequency 34.4-fold, and a mutation rate 13.8-fold higher than the wild type. All strains demonstrated specific mutational hotspots. Each single mutant had higher spontaneous mutation frequency than wild type at base substitution (G:C -> A:T). The mutational response was further increased in the double and triple mutants. The higher mutation rate and mutational response in ME3 suggested that the three homologs had non-overlapped and overlapped substrate spectrum in endogenous oxidative DNA repair.