Götz F, Schulze-Forster K, Wagner H, Kröger H, Simon D
Robert Koch-Institut, Berlin, F.R.G.
Biochim Biophys Acta. 1990 Nov 30;1087(3):323-9. doi: 10.1016/0167-4781(90)90006-n.
SV40 DNA was methylated in vitro with prokaryotic or eukaryotic DNA cytosine-5-methyltransferases and the inhibition of transcription by methylation was studied in Xenopus oocytes. Methylation with the prokaryotic HhaI or HpaII methyltransferases did essentially not inhibit transcription of SV40. Methylation with a rat liver methyltransferase led only to minor inhibition of the SV40 early genes, but to a complete shut shut off of the SV40 late genes. Partial methylation showed that methylation of both, the regulatory region and the 5' end of the SV40 late genes, was necessary for the effect on transcription. The TK gene could be inactivated by eukaryotic methylation of either the promoter and the first 50 nucleotides of the gene or the 3' rest of the gene. Insertion of the SV40 enhancer, not containing methylatable CpGs, into the TK upstream region, had no influence on the inhibition of TK gene transcription by methylation.
用原核或真核DNA胞嘧啶-5-甲基转移酶对SV40 DNA进行体外甲基化，并在非洲爪蟾卵母细胞中研究甲基化对转录的抑制作用。用原核HhaI或HpaII甲基转移酶进行甲基化基本上不抑制SV40的转录。用大鼠肝脏甲基转移酶进行甲基化仅对SV40早期基因有轻微抑制作用，但能使SV40晚期基因完全关闭。部分甲基化表明，SV40晚期基因的调控区和5'端的甲基化对转录效应都是必需的。通过对TK基因启动子和基因的前50个核苷酸或基因的3'端其余部分进行真核甲基化，可使TK基因失活。将不含可甲基化CpG的SV40增强子插入TK上游区域，对甲基化抑制TK基因转录没有影响。
