Huang P H, Stewart B W
Cancer Lett. 1978 Sep;5(3):161-6. doi: 10.1016/s0304-3835(78)80033-0.
DNA isolated from the livers of rats treated with a non-necrotizing dose of [14C]dimethylnitrosamine was fractionated by chromatography of benzoylated-DEAE-cellulose. The preparations of native DNA and DNA containing single stranded regions were then hydrolysed and amounts of methylated guanine determined. Four hours after dimethylnitrosamine treatment there was no difference in the levels of 7-methylguanine and O6-methylguanine in the 2 DNA fractions. By 24 h, although there was no difference in the amount of 7-methylguanine between the DNA fractions, there was a 10-fold difference in the level of O6-methylguanine. The elimination of O6-methylguanine from the fraction of DNA containing single stranded regions is discussed in terms of differing repair processes initiated by 7-methylguanine and O6-methylguanine.
从用非致死剂量的[14C]二甲基亚硝胺处理的大鼠肝脏中分离出的DNA，通过苯甲酰化-二乙氨基乙基纤维素色谱法进行分级分离。然后将天然DNA和含有单链区域的DNA制剂水解，并测定甲基化鸟嘌呤的含量。二甲基亚硝胺处理4小时后，两种DNA组分中7-甲基鸟嘌呤和O6-甲基鸟嘌呤的水平没有差异。到24小时时，尽管DNA组分之间7-甲基鸟嘌呤的含量没有差异，但O6-甲基鸟嘌呤的水平存在10倍的差异。根据由7-甲基鸟嘌呤和O6-甲基鸟嘌呤引发的不同修复过程，讨论了从含有单链区域的DNA组分中消除O6-甲基鸟嘌呤的情况。
