DNMT1 associates with the DNA replication fork and functions as a hemi-methylase responsible for maintaining correct methylation patterns on DNA replication.
The DNA of vertebrates contains tissue-specific patterns of methylated cytosine residues. These methylation patterns are transmitted by clonal inheritance through the strong preference of mammalian DNA (cytosine-5)-methyltransferase for hemimethylated DNA.
Methylation patterns are established during early embryogenesis and gametogenesis, although little is known of the molecular mechanisms that control sequence-specific de novo methylation and demethylation.
DNA (cytosine-5-)-methyltransferase 1 (DNMT1) is the principal enzyme responsible for maintaining CpG methylation and is required for embryonic development and survival of somatic cells in mice.
See also
DNMTs (DNA methyltransferases)
References
Chen T, Hevi S, Gay F, Tsujimoto N, He T, Zhang B, Ueda Y, Li E. Complete inactivation of DNMT1 leads to mitotic catastrophe in human cancer cells. Nat Genet. 2007 Mar;39(3):391-6. PMID: 17322882