Homo sapiens ACA45 scaRNA
This H/ACA box RNA was cloned by Kiss et al. (2004) from a HeLa cell extract immunoprecipitated with an anti-GAR1 antibody. It is predicted to guide the pseudouridylation of residue U37 of the U2 spliceosomal snRNA. The pseudouridylation of this residue was previously reported by Shibata et al. (1975). As other modification guides of RNA pol II-transcribed spliceosomal snRNAs, ACA45 presumably resides in Cajal bodies.
A small fraction of ACA45 is converted by a Dicer-dependant, Drosha/DGCR8-independant, mechanism into a 20-22 nt RNA that functions as a microRNA (Ender et al., 2008).