No-go decay (NGD) is one of several mRNA surveillance systems dedicated to the removal of defective mRNAs from the available pool. Two interacting factors, Dom34 and Hbs1, are genetically implicated in NGD in yeast. Here we show, using a reconstituted yeast translation system, that Dom34:Hbs1 interacts with the ribosome to promote subunit dissociation and peptidyl-tRNA drop-off. Our data further indicate that these recycling activities are shared by the homologous translation termination factor complex, eRF1:eRF3, suggesting a common ancestral function. As Dom34:Hbs1 activity exhibits no dependence on either peptide length or A-site codon identity, we propose that this quality-control system functions broadly to recycle ribosomes throughout the translation cycle whenever stalls occur.
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