Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2002 Aug;3(8):726-7.
doi: 10.1093/embo-reports/kvf154.

New clues to the function of the Cajal body

Maria Carmo-Fonseca  1
Affiliations
Review

New clues to the function of the Cajal body

Maria Carmo-Fonseca. EMBO Rep. 2002 Aug.
No abstract available

PubMed Disclaimer

Figures

None
Fig. 1. (A) Processing of spliceosomal U snRNAs. The U1, U2, U4 and U5 spliceosomal snRNAs are synthesized in the nucleoplasm by RNA polymerase II as immature precursors containing a 5′-terminal 7-mono-methylguanosine cap and extra nucleotides at the 3′ end (for simplicity, only the U5 snRNA is depicted). These RNAs are rapidly exported to the cytoplasm, where they bind to Sm proteins. The association of Sm proteins allows subsequent hyper-methylation of the 5′-cap and 3′-end maturation of the snRNA. The newly assembled snRNPs (small nuclear ribonucleoprotein particles) are then transported back into the nucleus, where the snRNAs further undergo 2′-O-ribose methylation (Me) and pseudouridine formation (Ψ). The new data reported by Darzacq et al. (2002) suggest that these modifications are guided by the U85, U87, U88, U89, U90, U91 and U92 small RNAs located in the Cajal body (scaRNAs). Modified nucleotides are confined to the functionally important regions of snRNAs. (B) Processing of the U3 snoRNA. The U3 snoRNA is synthesized in the nucleoplasm by RNA polymerase II as a 3′-extended precursor with a mono-methylated 5′ cap. Cap tri-methylation is catalysed by the methyl-transferase Tgs1/PIMT, which localizes to the Cajal body as shown by Verheggen et al. (2002). Following 3′-end processing, which also takes place within the Cajal body, the U3 RNA binds fibrillarin (Fib) and other core snoRNP proteins. The mature U3 snoRNPs leave the Cajal body to accumulate in the nucleolus.
None
Maria Carmo-Fonseca
See this image and copyright information in PMC

References

    1. Darzacq X., Jády, B.E., Verheggen, C., Kiss, A.M., Bertrand, E. and Kiss, T. (2002) Cajal body-specific small nuclear RNAs: a novel class of 2′-O-methylation and pseudouridylation guide RNAs. EMBO J., 21, 2746–2756. - PMC - PubMed
    1. Filipowicz W. and Pogacic, V. (2002) Biogenesis of small nucleolar ribonucleoproteins. Curr. Opin. Cell Biol., 14, 319–327. - PubMed
    1. Gall J.G. (2000) Cajal bodies: the first 100 years. Annu. Rev. Cell Dev. Biol., 16, 273–300. - PubMed
    1. Jády B.E. and Kiss, T. (2001) A small nucleolar guide RNA functions both in 2′-O-ribose methylation and pseudouridylation of the U5 spliceosomal RNA. EMBO J., 20, 541–551. - PMC - PubMed
    1. Mouaikel J., Verheggen, C., Bertrand, E., Tazi, J. and Bordonne, R. (2002) Hypermethylation of the cap structure of both yeast snRNAs and snoRNAs requires a conserved methyltransferase that is localized to the nucleolus. Mol. Cell, 9, 891–901. - PubMed

MeSH terms