Is DNA methylation reversible?
Posted January 22, 2021
Answer
Yes, DNA methylation is a reversible process that can occur actively or passively in mammals.
- Active DNA demethylation refers to the direct removal of a methyl group from 5-methylcytosine via an enzymatic process. For example, ten-eleven translocation (TET) methylcytosine dioxygenases are a family of enzymes that catalyze the stepwise oxidation of methylated cytosine in DNA to 5-hydroxymethylcyotsine, which is further oxidize to 5-formylcytosine (5fC) and 5-carboxycytosine (5caC). Through base excision repair cells remove these oxidation products so that it can be replaced by cytosine.
- Passive DNA demethylation refers to the reduction of methylated cytosine during successive cycles of DNA replication without DNMT1and UHRF1present.
Additional resources
Reversing DNA methylation: mechanisms, genomics, and biological functions
6-TET, SE [6-Carboxy-2',4,7',7-tetrachlorofluorescein, succinimidyl ester]