Klaude M, von der Decken A
J Natl Cancer Inst. 1984 Oct;73(4):909-13.
Protein diets deficient or enriched in DL-methionine were studied for the effect of methylation of nuclear components in subadult and adult outbred albino male mice given N-nitrosodimethylamine. After the mice were fed diets for 6 days, they were given ip injections of [14C]N-nitrosodimethylamine (5 mg/kg body wt) and killed 45 minutes later. Liver nuclei were isolated; incorporation of 14C into nuclear proteins and methylation of DNA and RNA were determined. In the subadult and adult animals the nuclear protein content was diminished by shortage of a single essential amino acid. Incorporation of 14C into the total protein was reduced. The reduction amounted to 55% in the subadult and 23% in the adult animals. Neither an age-dependent nor a diet-dependent change in the specific methylation of DNA and RNA was observed. Analysis of methylation of DNA and RNA was observed. Analysis of methylated purine bases showed an age-related rise in O6-methylguanine in the adult as compared with the subadult mice.
研究了缺乏或富含DL-蛋氨酸的蛋白质饮食对给予N-亚硝基二甲胺的未成年和成年远交白化雄性小鼠核成分甲基化的影响。小鼠喂食饮食6天后，腹腔注射[14C]N-亚硝基二甲胺（5 mg/kg体重），45分钟后处死。分离肝细胞核；测定14C掺入核蛋白以及DNA和RNA的甲基化情况。在未成年和成年动物中，单一必需氨基酸的缺乏会使核蛋白含量减少。14C掺入总蛋白的量减少。未成年动物中减少了55%，成年动物中减少了23%。未观察到DNA和RNA特异性甲基化的年龄依赖性或饮食依赖性变化。观察了DNA和RNA甲基化的分析。甲基化嘌呤碱的分析表明，与未成年小鼠相比，成年小鼠中O6-甲基鸟嘌呤随年龄增加。
