Homo sapiens C/D box snoRNA U36A. This snoRNA is an human orthologue of chicken U36 snoRNA, initially characterized by a bioinformatics search for C/D motives in a vertebrate intron database (Nicoloso et al. 1996). It is predicted to guide the 2'O-ribose methylation of 18S rRNA A668. U36A shares the same host gene with the C/D box snoRNAs U36B, U36C and U24 (RPL7A).
In fishes, xenopus, opossum and rat (but not mouse), U36A is predicted to guide the methylation of both 18S rRNA A668 (human numbering) and 28S rRNA A3703 (as U36C). The proposed nomenclature of vertebrate U36A, B and C is based on sequence alignments rather than position in the conserved RPL7A host gene.