Klaude M, von der Decken A
Comp Biochem Physiol C Comp Pharmacol Toxicol. 1985;81(1):19-23. doi: 10.1016/0742-8413(85)90085-4.
Mice were injected i.p. with a single dose (5 mg/kg body wt) of [14C]dimethylnitrosamine and killed at time intervals between 15 and 120 min. Isolated nuclei were incubated with micrococcal nuclease and the chromatin separated into a 1100 g pellet P1 and supernatant fraction S1. The incorporation of 14C from [14C]dimethylnitrosamine into chromatin was significantly higher in the P1 than the S1 fraction. The purine bases of the P1 DNA showed a lower methylation than those of the S1 DNA. In contrast, radioactivity of the proteins was higher in the P1 than the S1 fraction. It is concluded that the open structures of the S1 chromatin were preferentially attacked by the hepatotoxin leading to a high 14C-labelling of the DNA relative to that of the proteins.
给小鼠腹腔注射单剂量（5毫克/千克体重）的[14C]二甲基亚硝胺，并在15至120分钟的时间间隔处死。将分离的细胞核与微球菌核酸酶一起孵育，染色质分离成1100克沉淀P1和上清液组分S1。[14C]二甲基亚硝胺中的14C掺入染色质在P1中比在S1组分中显著更高。P1 DNA的嘌呤碱甲基化程度低于S1 DNA。相反，蛋白质的放射性在P1中比在S1组分中更高。得出的结论是，S1染色质的开放结构优先受到肝毒素的攻击，导致DNA相对于蛋白质有较高的14C标记。
