Transcript-specific translational regulation in the unfolded protein response of Saccharomyces cerevisiae

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) causes stress and induces the unfolded protein response (UPR). Genome-wide analysis of translational regulation in response to the UPR-inducing agent dithiothreitol in Saccharomyces cerevisiae is reported. Microarray analysis, confirmed using qRT-PCR, identified transcript-specific translational regulation. Transcripts with functions in ribosomal biogenesis and assembly were translationally repressed. In contrast, mRNAs from known UPR genes, encoding the UPR transcription factor Hac1p, the ER-oxidoreductase Ero1p and the ER-associated protein degradation (ERAD) protein Der1p, were enriched in polysomal fractions, indicating translational up-regulation. Splicing of HAC1 mRNA is shown to be required for efficient ribosomal loading.