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Spliceosomal Small Nuclear Ribonucleoprotein Particles Repeatedly Cycle through Cajal Bodies
- Publication Year :
- 2008
- Publisher :
- The American Society for Cell Biology, 2008.
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Abstract
- The Cajal body (CB) is a nuclear structure closely associated with import and biogenesis of small nuclear ribonucleoprotein particles (snRNPs). Here, we tested whether CBs also contain mature snRNPs and whether CB integrity depends on the ongoing snRNP splicing cycle. Sm proteins tagged with photoactivatable and color-maturing variants of fluorescent proteins were used to monitor snRNP behavior in living cells over time; mature snRNPs accumulated in CBs, traveled from one CB to another, and they were not preferentially replaced by newly imported snRNPs. To test whether CB integrity depends on the snRNP splicing cycle, two human orthologues of yeast proteins involved in distinct steps in spliceosome disassembly after splicing, hPrp22 and hNtr1, were depleted by small interfering RNA treatment. Surprisingly, depletion of either protein led to the accumulation of U4/U6 snRNPs in CBs, suggesting that reassembly of the U4/U6·U5 tri-snRNP was delayed. Accordingly, a relative decrease in U5 snRNPs compared with U4/U6 snRNPs was observed in CBs, as well as in nuclear extracts of treated cells. Together, the data show that particular phases of the spliceosome cycle are compartmentalized in living cells, with reassembly of the tri-snRNP occurring in CBs.
- Subjects :
- Small interfering RNA
Spliceosome
Ribonucleoprotein, U4-U6 Small Nuclear
Coiled Bodies
Biology
environment and public health
Humans
snRNP
RNA, Small Interfering
Molecular Biology
Ribonucleoprotein, U5 Small Nuclear
Yeast Proteins
RNA-Binding Proteins
Cell Biology
Articles
Ribonucleoproteins, Small Nuclear
Molecular biology
Survival of Motor Neuron 1 Protein
Cell biology
Cajal body
RNA splicing
Spliceosomes
Carrier Proteins
Small nuclear ribonucleoprotein
Biogenesis
Biomarkers
HeLa Cells
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....a46dd06c572f91a4e754ae804625206e