The presence of 5-methylcytosine in genomic DNA is the result of enzymatic activity of the C5 DNA methyltransferases, which catalyze the transfer of a methyl group from S-adenosyl- L-methionine (AdoMet).
DNA 甲基化转移酶有两种活性:
一、maintenance
DNA复制过程中,对称的CG和CXG序列变为半甲基化,需要保持活性。
二、 de novo
甲基化之前未甲基化的C位点。对于保持非对称的C位点,在复制过程中,也需要初始甲基化。
DNA甲基化酶的类型:
Dnmt1MET1 class, the Dnmt2 class, the CMT class, and Dnmt3 class
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