One role of messenger RNA (mRNA) degradation is to maintain the fidelity of gene expression by degrading aberrant transcripts. Recent results show that mRNAs without translation termination codons are unstable in eukaryotic cells. We used yeast mutants to demonstrate that these "nonstop" mRNAs are degraded by the exosome in a 3'-to-5' direction. The degradation of nonstop transcripts requires the exosome-associated protein Ski7p. Ski7p is closely related to the translation elongation factor EF1A and the translation termination factor eRF3. This suggests that the recognition of nonstop mRNAs involves the binding of Ski7p to an empty aminoacyl-(RNA-binding) site (A site) on the ribosome, thereby bringing the exosome to a mRNA with a ribosome stalled near the 3' end. This system efficiently degrades mRNAs that are prematurely polyadenylated within the coding region and prevents their expression.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|