Dimethyl sulfoxide stimulates the catalytic activity of de novo DNA methyltransferase 3a (Dnmt3a) in vitro.

Mammalian DNA methyltransferase Dnmt3a is required for de novo methylation of CpG dinucleotides in genomic DNA. While DNA methyltransferase inhibitors have been extensively utilized both in vitro and in vivo, no stimulator of catalytic activity has been identified thus far. Here we show that the methyltransfer activity of Dnmt3a is stimulated by the addition of dimethyl sulfoxide (DMSO) to the reaction solution in vitro. Enzymatic analysis of initial reaction velocity suggests that the DMSO stimulation effect depends on the interaction between DMSO and the reaction substrates (DNA and AdoMet), but not the enzyme itself.