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Updated: Jul 17, 2026
09:31
Heterokaryon Technique for Analysis of Cell Type-specific Localization
Published on: March 11, 2011
Box C/D small nucleolar RNA trafficking involves small nucleolar RNP proteins, nucleolar factors and a novel nuclear
C Verheggen1, J Mouaikel, M Thiry
1IGMM, IFR 24, UMR 5535 du CNRS, 34293 Montpellier Cedex 5, France.
The EMBO Journal
|September 28, 2001
Summary
Small nucleolar RNAs (snoRNAs) require specific proteins for proper localization within the cell. This study reveals that snoRNP assembly occurs in the nucleoplasm or nucleolar bodies before reaching ribosome synthesis sites.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Nucleolar localization of box C/D small nucleolar (sno) RNAs is crucial for their function.
- In vertebrates, this process involves Cajal bodies (CB), but the pathway in yeast is less understood.
- The human survival of motor neuron protein (SMN) is a marker for gems/CB.
Purpose of the Study:
- To investigate the sub-nucleolar localization pathway of box C/D snoRNAs in yeast.
- To explore the role of specific nucleolar proteins and core snoRNP proteins in this pathway.
- To compare yeast nucleolar bodies (NB) with vertebrate Cajal bodies (CB).
Main Methods:
- Overexpression of a box C/D reporter snoRNA in yeast.
- Localization studies of the reporter snoRNA and human SMN protein.
- Genetic manipulation involving mutations in Srp40 and Nsr1p.
- Depletion of core snoRNP proteins (Nop1p/fibrillarin, Snu13p, Nop56p, Nop5p/Nop58p).
Main Results:
- Overexpression of box C/D reporter snoRNA caused accumulation in the nucleolar body (NB).
- Human SMN protein localized to the NB in yeast, suggesting structural similarities between NB and CB.
- Mutations in Srp40 and Nsr1p affected snoRNA accumulation in the NB.
- Depletion of core snoRNP proteins led to delocalization of snoRNAs to the nucleoplasm.
Conclusions:
- SnoRNP assembly likely occurs in the nucleoplasm or during transit through the NB.
- The NB serves as an intermediate station for box C/D snoRNA localization.
- Complete snoRNPs are then routed to sites of ribosome synthesis.
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