The undertranslated transcriptome reveals widespread translational silencing by alternative 5' transcript leaders

摘要: Translational efficiencies in Saccharomyces cerevisiae vary from transcript to by approximately two orders of magnitude. Many the poorly translated transcripts were found respond appropriate external stimulus recruiting ribosomes. Unexpectedly, a high frequency these showed appearance altered 5' leaders that coincide with increased ribosome loading. Of detectable S. cerevisiae, 8% be underloaded Gene ontology categories responses stress or stimuli overrepresented this population transcripts. Seventeen loaded involved pheromone, nitrogen starvation, and osmotic selected for detailed study environmental signal Twelve regulated exhibited structural changes their response signal. In many coding region remained intact, whereas shortening end truncated open reading frame others. Colinearity between gene sequences eliminated splicing as mechanism alterations structure. Frequent occurrence coordinated structure translation efficiency, at least three different regulatory networks, suggests widespread phenomenon. It is likely arose promoter usage. We speculate production translationally silenced may one allowing low-level transcription activity necessary maintaining an chromatin while not inappropriate protein production.