An RNA granule for translation quality control in Saccharomyces cerevisiae

Abstract

Cytoplasmic RNA granules compartmentalize phases of the translation cycle in eukaryotes. We previously reported the localization of oxidized RNA to cytoplasmic foci called oxidized RNA bodies (ORBs) in human cells. We show here that ORBs are RNA granules in Saccharomyces cerevisiae. Several lines of evidence support a role of ORBs in the compartmentalization of no-go decay and ribosome quality control, the translation quality control pathways that recognize and clear aberrant mRNAs, including those with oxidized bases. Translation is required by these pathways and ORBs. Translation quality control factors localize to ORBs. A substrate of translation quality control, a stalled mRNA-ribosome-nascent chain complex, localizes to ORBS. Translation quality control mutants have altered ORB numbers, sizes, or both. In addition, we identify 68 ORB proteins, by immunofluorescence staining directed by proteomics, which further support their role in translation quality control and reveal candidate new factors for these pathways.