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. NSUN2 encodes a methyltransferase that catalyzes the intron-dependent formation of 5-methylcytosine at C34 of tRNA-leu(CAA) (Brzezicha et al., 2006 [PubMed 17071714]).