DNA methylation is mediated by a conserved family of DNA methyltransferases (Dnmts). The human genome encodes three active Dnmts (Dnmt1, Dnmt3a and Dnmt3b), the tRNA methyltransferase Dnmt2, and the regulatory protein Dnmt3L. in addition to its DNA methylating activity, DNMT1 can act on gene transcription by modulating permissive H3K4 and repressive H3K27 trimethylation in developing inhibitory interneurons similar to what was found in other cell types. In particular, the transcriptional control of Pak6 was accomplished by interactions of DNMT1 with the Polycomb-repressor complex 2 (PCR2) core enzyme EZH2, mediating repressive H3K27 trimethylation at regulatory regions of the Pak6 gene locus. DNMT1 in promoting interneuron migration through the transcriptional control over key genes like Pak6 achieved by a crosstalk with histone tail methylation.

>70% as determined by SDS-PAGE.