METTL1 is known as tRNA (guanine-N(7)-)-methyltransferase which belongs to the methyltransferase superfamily. METTL1 shows high sequence similarity to yeast ORF YDL201w and has been shown to be inactivated by phosphorylation. This protein contains a conserved S-adenosylmethionine-binding motif and is inactivated by phosphylation. It catalyzes the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA.