Ather A, Ahmed Z, Riazuddin S
Nucleic Acids Res. 1984 Feb 24;12(4):2111-26. doi: 10.1093/nar/12.4.2111.
Wild type M. luteus cells have been adapted by a step-wise treatment with sub-lethal concentrations of MNNG. The adapted cells exhibit 5.7 fold increased resistance to the killing effects of the mutagen and a simultaneous efficient removal of various base modifications present in cellular DNA. A protein extract prepared from adapted cells contains inducible repair functions which can reduce 80-90% of the alkylated DNA content of 06-MeG is effected by a transmethylase and there is no concomitant release of the modified base. However, N-3 MeG is released as a free modified base through the action of a DNA glycosylase. The release of N-3 MeA is unaffected by the induction treatment whereas that of N-7 methylpurine is slightly improved in the adapted cells.
野生型藤黄微球菌细胞通过用亚致死浓度的MNNG进行逐步处理而得到适应。适应后的细胞对诱变剂的杀伤作用表现出5.7倍的抗性增加，同时能有效去除细胞DNA中存在的各种碱基修饰。从适应细胞制备的蛋白质提取物含有可诱导的修复功能，可将06 - MeG的烷基化DNA含量降低80 - 90%，这是由一种转甲基酶实现的，并且没有伴随修饰碱基的释放。然而，N - 3 MeG通过DNA糖基化酶的作用作为游离修饰碱基释放出来。N - 3 MeA的释放不受诱导处理的影响，而在适应细胞中N - 7甲基嘌呤的释放略有改善。
