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7The yeast mRNA-binding protein Npl3p interacts with the cap-binding complex.
E C Shen1, T Stage-Zimmermann, P Chui
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and the Dana Farber Cancer Institute, Boston, Massachusetts 02115, USA.
The Journal of Biological Chemistry
|May 24, 2000
Summary
The study reveals a synthetic lethal relationship between NPL3 and the cap-binding complex (CBP80/CBP20) in yeast, suggesting their interaction is crucial for mRNA export. This highlights a novel pathway for nuclear mRNA processing and transport.
Area of Science:
- Molecular Biology
- Yeast Genetics
- RNA Biology
Background:
- Npl3p is an essential RNA-binding protein in S. cerevisiae, with temperature-sensitive mutants showing mRNA export defects.
- The cap-binding complex (CBP80/CBP20) plays a role in mRNA processing and export.
Purpose of the Study:
- To investigate the genetic and physical interactions between NPL3 and the cap-binding complex.
- To elucidate the role of Npl3p and the cap-binding complex in mRNA nuclear export.
Main Methods:
- Genetic analysis using temperature-sensitive npl3 alleles and deletions of CBP80/CBP20.
- Co-immunoprecipitation experiments to assess protein interactions.
- Analysis of Cbp80p shuttling between nucleus and cytoplasm.
Main Results:
- A synthetic lethal relationship was observed between certain npl3 mutants and CBP80 or CBP20 deletions.
- Npl3p specifically co-precipitated with Cbp80p and Cbp20p.
- Npl3p-Cbp80p interaction is dependent on Cbp20p and RNA; Cbp80p shuttles between nucleus and cytoplasm dependent on RNA synthesis.
Conclusions:
- Npl3p and the cap-binding complex interact physically and genetically, indicating a functional link in mRNA export.
- These findings support a model of co-transcriptional mRNA packaging by Npl3p and the cap-binding complex for nuclear export.