Anti-NOP2/Sun RNA methyltransferase 3 antibodies are used for the immunodetection of the protein encoded by the NSUN3 gene. In humans, the canonical protein has a reported length of 340 amino acid residues and a mass of 38.2 kDa. Its subcellular localization is in the mitochondria. It is a member of the RsmB/NOP protein family. The gene encoding this protein is implicated in Combined oxidative phosphorylation deficiency. Other names for this target antigen include NOL1/NOP2/Sun domain family member 3, NOP2/Sun RNA methyltransferase family member 3, putative methyltransferase NSUN3, and tRNA (cytosine(34)-C(5))-methyltransferase, mitochondrial. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.