Davis T, Rinaldi A, Clark L, Adams R L
Biochim Biophys Acta. 1986 May 5;866(4):233-41. doi: 10.1016/0167-4781(86)90048-5.
The endogenous DNA methylase in nuclei isolated from growing mouse cells preferentially methylates DNA in micrococcal nuclease-resistant regions probably as a result of the location in these regions of the preponderance of hemimethylated sites. Added mouse ascites cell DNA methylase catalyses the methylation of exposed, nuclease-sensitive DNA in chromatin from growing or non-growing mouse or insect cells. The poor acceptor ability of nuclease-resistant regions in this situation is due to the presence of histone proteins which block de novo methylation. Transcriptionally active regions of chromatin are selectively methylated in vitro by either endogenous or added DNA methylase.
从小鼠生长细胞中分离出的细胞核内的内源性DNA甲基化酶优先使微球菌核酸酶抗性区域的DNA甲基化，这可能是由于这些区域中半甲基化位点占优势的缘故。添加的小鼠腹水细胞DNA甲基化酶催化来自生长或非生长小鼠或昆虫细胞的染色质中暴露的、核酸酶敏感的DNA的甲基化。在这种情况下，核酸酶抗性区域的接受能力较差是由于存在组蛋白，它们会阻止从头甲基化。染色质的转录活性区域在体外可被内源性或添加的DNA甲基化酶选择性地甲基化。
