Small Cajal body specific RNA 17

Small Cajal body-specific RNA 17 (also known as U12-22 scaRNA) is a type of small nuclear RNA which localises to the cajal bodies and proposed to guide the modification of RNA polymerase II transcribed spliceosomal RNAs U1, U2, U4, U5 and U12.[1][2]

small Cajal body-specific RNA 17
Predicted secondary structure and sequence conservation of SCARNA17
Identifiers
Symbol	SCARNA17
Alt. Symbols	snoU12-22
Rfam	RF00492
Other data
RNA type	Gene; snRNA; snoRNA; scaRNA
Domain(s)	Eukaryota
GO	GO:0006396 GO:0015030 GO:0005730
SO	SO:0000275
PDB structures	PDBe

The complete human U12-22/U4-8 scaRNA is composed of two tandem C/D box domains (termed U12-22 and U4-8). The 5' and 3' C/D domains are predicted to guide the 2'O-ribose methylation of residue U22 in U12 and residue C8 in U4 snRNAs respectively.[1] This family includes only the 5' C/D box domain (U12-22) as the 3' C/D box is represented by Small Cajal body specific RNA 18. The 3' C/D domain (U4-8) was also cloned previously by Darzacq and called U91.[3] Both the doublet (U12-22/U4-8) and singlet (U4-8) forms of this snRNA have been purified from HeLa cells. [1] The doublet form U12-22/U4-8 has been shown to localise to the nucleoplasm and is proposed to reside in the Cajal bodies whereas the U4-8 single domain appears to accumulate in the nucleolus. [1] In humans the genomic location of U12-88/U4-8 is intergenic and the purified transcript has been shown to possess a methylated guanosine cap suggesting it is independently transcribed by RNA polymerase II.[1]