Small Cajal body specific RNA 15 (also known as SCARNA15 or ACA45) is a
small nucleolar RNA
In molecular biology, Small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, t ...
found in
Cajal bodies and believed to be involved in the pseudouridylation (
isomerisation
In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure. Enolization is an example of isomerization, as is tautomeriz ...
of
uridine to
pseudouridine) of
U1 spliceosomal RNA.
scaRNAs are a specific class of
small nucleolar RNA
In molecular biology, Small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, t ...
s that localise to the
Cajal bodies and guide the modification of
RNA polymerase II transcribed
spliceosomal
A spliceosome is a large ribonucleoprotein (RNP) complex found primarily within the nucleus of eukaryotic cells. The spliceosome is assembled from small nuclear RNAs (snRNA) and numerous proteins. Small nuclear RNA (snRNA) molecules bind to speci ...
RNAs
U1,
U2,
U4,
U5 and
U12.
ACA45 belongs to the
H/ACA box class of guide RNAs as it has the predicted hairpin-hinge-hairpin-tail structure, the conserved H/ACA-box motifs and is found associated with GAR1.
ACA45 is predicted to guide the pseudouridylation of residue U37 of the U2 spliceosomal snRNA.
It has been shown that human ACA45 can be processed into a 21
nucleotides long mature
miRNA by the
RNAse III family endoribonuclease dicer.
This snoRNA product has previously been identified as mmu-miR-1839
and was shown to be processed independent of the other miRNA generating
endoribonuclease drosha.
References
External links
*
*
Small nuclear RNA
Spliceosome
RNA splicing
{{molecular-cell-biology-stub