Yeast hEST1A/B (SMG5/6)–Like Proteins Contribute to Environment-Sensing Adaptive Gene Expression Responses

摘要

During its natural life cycle, budding yeast (Saccharomyces cerevisiae) has to adapt to drastically changing environments, but how environmental-sensing pathways are linked to adaptive gene expression changes remains incompletely understood. Here, we describe two closely related yeast hEST1A-B (SMG5-6)–like proteins termed and that contain a 14-3-3–like domain and a putative PilT N-terminus ribonuclease domain. We found that, unlike their metazoan orthologs, and were not involved in nonsense-mediated mRNA decay or telomere maintenance pathways. However, in genome-wide expression array analyses, absence of and led to more than two-fold deregulation of ∼50 transcripts, most of which were expressed inversely to the appropriate metabolic response to environmental nutrient supply; for instance, normally glucose-repressed genes were derepressed in Δ Δ double mutants during growth in a high-glucose environment. Likewise, in a genome-wide synthetic gene array screen, Δ Δ double mutants were synthetic sick with null mutations for and , which form the environmental-sensing complex of the pH response gene expression pathway. Overall, these results suggest that and contribute to the regulation of adaptive gene expression responses of environmental sensing pathways.