Dnmt2 was initially assigned a member of the DNA methyltransferase family on the basis of its extensive homology with eukaryotic and prokaryotic DNA-(cytosine C5)-methyltransferases . However, in the apparent absence of a phenotype in dnmt2 knockout cells, Dnmt2's possible biological function remained unknown , even though Dnmt2 is strongly conserved and it is found in species ranging from Schizosaccharomyces pombe to human. Later very weak, residual DNA methylation activity was found with enzymes from different species. The finding that Dnmt2 is an active RNA methyltransferase capable of methylating the C38 position of the tRNA Asp came as a surprise . However, still no cellular function of the tRNA Asp methylation has been found, although in Zebrafish Dnmt2 knock-down caused a developmental phenotype . It is very intriguing that an enzyme that looks like a DNA methyltransferase can methylate RNA, in particular since the RNA and DNA specific m5 C methyltransferases use different catalytic residues and a different mechanism for the methyl transfer reaction . the predicted molecular weight of Dnmt2 is 45 kDa, but it may migrate to the 40 kDa (PMID: 18567810 )