Translational attenuation mediated by an mRNA intron

摘要: Abstract Background: The unfolded protein response (UPR) is an intracellular signaling pathway that activated by the accumulation of proteins in endoplasmic reticulum (ER). UPR results increase transcription ER-resident facilitate folding ER. A key regulatory step activation regulated splicing HAC1 mRNA, which encodes Hac1p, a factor dedicated to this pathway. Hac1p can be detected only when spliced form mRNA (termed i for nduced) produced; was surprising because unspliced u ( ninduced) equally stable cells. Results: We show contrast most other pre-mRNAs, transported from nucleus into cytosol. Although associated with polyribosomes, no detectable produced unless intron removed, indicating presence prevents translation. When it produced, has stability similar , and differs short carboxy-terminal tail sequence. however, differently modified less active activating transcription. Interestingly, transplanted 3′ untranslated region completely unrelated sufficient attenuate translation preceding open reading frame. Conclusions: have shown both necessary prevent complete polyribosome-associated mRNAs. To our knowledge, identifies new way attenuated.