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 [Esl1][1] and [Esl2][2] that contain a 14-3-3–like domain and a putative PilT N-terminus ribonuclease domain. We found that, unlike their metazoan orthologs, [Esl1][1] and [Esl2][2] were not involved in nonsense-mediated mRNA decay or telomere maintenance pathways. However, in genome-wide expression array analyses, absence of [Esl1][1] and [Esl2][2] 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 [esl1][1]Δ [esl2][2]Δ double mutants during growth in a high-glucose environment. Likewise, in a genome-wide synthetic gene array screen, [esl1][1]Δ [esl2][2]Δ double mutants were synthetic sick with null mutations for [Rim8][3] and [Dfg16][4], which form the environmental-sensing complex of the [Rim101][5] pH response gene expression pathway. Overall, these results suggest that [Esl1][1] and [Esl2][2] contribute to the regulation of adaptive gene expression responses of environmental sensing pathways. [1]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000001413 [2]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000001804 [3]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000003013 [4]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000005556 [5]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000001019.