Methylation Controls
DNA Methylation
CpG methylation by DNMT1 (maintenance) and DNMT3a/b (de novo) silences genes. TET enzymes oxidize 5mC→5hmC→demethylation. Promoter methylation silences; gene body methylation promotes transcription.
5-methylcytosine (5mC)
5-hydroxymethyl (5hmC)
Unmethylated CpG
DNMT1 (maintenance)
DNMT3a/b (de novo)
TET enzyme
Methylation level
Transcription level
TET activity