Homo sapiens U109 scaRNA.
This H/ACA box RNA was cloned by Gu et al. (2005) from blood cells by an RT-PCR method that preferentially amplifies H/ACA box snoRNAs. Its expression was evidenced by Northern blot. U109 is predicted to guide the pseudouridylation of residue U6 of the U1 spliceosomal snRNA. The pseudouridylation of this residue was previously reported by Reddy et al. (1981).
As other modification guides of RNA pol II-transcribed spliceosomal snRNAs, U109 presumably resides in Cajal bodies. In agreement, the conserved CAB box (Richard et al., 2003) resides in the loop of the 3’ stem.