MettL7B belongs to the methyltransferase superfamily. It is a probable methyltransferase. Methyltransferase is a type of transferase enzyme which transfers a methyl group from a donor to an acceptor. Often methylation occurs on nucleic bases in DNA or amino acids in protein structures. DNA methylation is often utilized to silence and regulate genes without changing the original DNA sequence. DNA methylation may be necessary for normal growth from embryonic stages in mammals. When mutant embryonic stem cells lacking the murine DNA methyltransferase gene were introduced to a germline of mice they caused a recessive lethal phenotype. Methylation may also be linked to cancer development as methylation of tumor suppressor genes promotes tumorgenesis and metastasis.