NSUN2 encodes a methyltransferase that catalyzes the intron-dependent formation of 5-methylcytosine at C34 of tRNA-leu(CAA). Maturation of cytoplasmic tRNAs includes splicing of introns, which are located 1 nucleotide 3-prime from the anticodon in all intron-containing tRNA genes. In tRNA-leu(CAA), the first position of the anticodon, C34, is converted to 5-methylcytosine, a modification necessary to stabilize the anticodon-codon pairing and correctly translate the mRNA. Mutations of NSUN2 result in autosomal recessive 5 mental retardation (MRT5).
5-methycytoisine methyltransferase; hTrm4; member 2; MISU; Myc-induced SUN domain-containing protein; Myc-induced SUN-domain-containing protein; NOL1/NOP2/Sun domain family; NOL1/NOP2/Sun domain family 2; NOL1/NOP2/Sun domain family member 2; NOL1/NOP2/Sun domain family, member 2; NOP2/Sun domain family, member 2; NOP2/Sun RNA methyltransferase family, member 2; SAKI; Substrate of AIM1/Aurora kinase B; TRM4; tRNA (cytosine(34)-C(5))-methyltr; tRNA (cytosine(34)-C(5))-methyltransferase; tRNA (cytosine-5-)-methyltransferase; tRNA (cytosine-5-)-methyltransferase NSUN2; tRNA methyltransferase 4 homolog