Methylation of DNA at cytosine residues is important in regulation of gene expression and genomic imprinting. Hypermethylation of CpG islands in tumor suppressor genes or hypomethylation of bulk genomic DNA may be linked to development of cancer. Thus far three families of mammalian DNA methyltransferase genes have been identified : DNMT1, DNMT2, and DNMT3. DNMT1 is constitutively expressed in proliferating cells, and inactivation of this gene causes global demethylation of genomic DNA and embryonic lethality. DNMT1 co-purifies with the retinoblastoma (Rb) tumor suppressor gene product E2F1 and with HDAC1. DNMT1 cooperates with Rb to repress transcription from promoters containing E2F-binding sites which suggests a link between DNA methylation, histone deacetylase and sequence specific DNA binding activity as well as a growth-regulatory pathway that is disrupted in cancer cells.
DNA (cytosine-5)-methyltransferase 1 CXXC-type zinc finger protein 9, CXXC9 DNA methyltransferase HsaI, DNA MTase HsaI, M.HsaI Gene name : DNMT1