Small Cajal body specific RNA 1
Predicted secondary structure of Small Cajal body specific RNA 1
Identifiers
Symbol	SCARNA1
Rfam	RF00553
Other data
RNA type	gene, snRNA, snoRNA, scaRNA;
Domain(s)	Vertebrata
PDB structures	PDBe

Small Cajal body-specific RNAs (scaRNAs) are a class of small nucleolar RNAs (snoRNAs) that specifically localise to the Cajal body, a nuclear organelle (cellular sub-organelle) involved in the biogenesis of small nuclear ribonucleoproteins (snRNPs or snurps). ScaRNAs guide the modification ( methylation and pseudouridylation) of RNA polymerase II transcribed spliceosomal RNAs U1, U2, U4, U5 and U12.

The first scaRNA identified was U85. ^[1] It is unlike typical snoRNAs in that it is a composite C/D box and H/ACA box snoRNAs and can guide both pseudouridylation and 2′-O-methylation. Not all scaRNAs are composite C/D and H/ACA box snoRNA and most scaRNAs are structurally and functionally indistinguishable from snoRNAs, directing ribosomal RNA (rRNA) modification in the nucleolus.

Drosophila scaRNAs

Several studies identified scaRNAs in Drosophila. ^{[1] [2] [3] [4] [5]} One of the studies showed that several Drosophila scaRNAs could function equally well in the nucleoplasm of mutant flies that lack Cajal bodies. ^[4] Further investigation showed that scaRNA pugU6-40 targets U6 snRNA, whose modification occurs in the nucleolus not CB and that pugU1-6 and pug U2-55 guide 2 RNAs: snRNA and 28s rRNA. ^[5]

Small Cajal body-specific RNA 1

In molecular biology, Small Cajal body-specific RNA 1 (also known as SCARNA1 or ACA35) is a small nucleolar RNA found in Cajal bodies and believed to be involved in the pseudouridylation of U2 spliceosomal RNA at residue U89.

scaRNA1 is a non-coding RNA, which are functional products of genes not translated into proteins. Such RNA molecules usually contain important secondary structure or ligand- binding motifs and are involved in many important biological processes in the cell. ^[6]

scaRNA1 belongs to the H/ACA box class of snoRNAs, as it has the predicted hairpin-hinge-hairpin-tail structure, conserved H/ACA-box motifs, and is found associated with GAR1 protein. ^[7]

References

External links

• snoRNAbase: human H/ACA and C/D box snoRNA database
• Page for Small Cajal body-specific RNA at Rfam

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