Activator and Repressor Functions of the Mot3 Transcription Factor in the Osmostress Response of Saccharomyces cerevisiae

Abstract

Mot3 and Rox1 are transcriptional repressors of hypoxic genes. Both factors recently have been found to be involved in the adaptive response to hyperosmotic stress, with an important function in the adjustment of ergosterol biosynthesis. Here, we determine the gene expression profile of a mot3 rox1 double mutant under acute osmostress at the genomic scale in order to identify the target genes affected by both transcription factors upon stress. Unexpectedly, we find a specific subgroup of osmostress-inducible genes to be under positive control of Mot3. These Mot3-activated stress genes also depend on the general stress activators Msn2 and Msn4. We confirm that both Mot3 and Msn4 bind directly to some promoter regions of this gene group. Furthermore, osmostress-induced binding of the Msn2 and Msn4 factors to these target promoters is severely affected by the loss of Mot3 function. The genes repressed by Mot3 and Rox1 preferentially encode proteins of the cell wall and plasma membrane. Cell conjugation was the most significantly enriched biological process which was negatively regulated by both factors and by osmotic stress. The mating response was repressed by salt stress dependent on Mot3 and Rox1 function. Taking our findings together, the Mot3 transcriptional regulator has unanticipated diverse functions in the cellular adjustment to osmotic stress, including transcriptional activation and modulation of mating efficiency.

Set4 is a chromatin-associated protein, promotes survival during oxidative stress, and regulates stress response genes in yeast

“…Set4 may be able to both activate and repress genes, particularly in a condition-specific manner. Similar behavior has been characterized for a number of stress-responsive transcription factors, including Hap1, Mot3, and Rox1 (40,41).…”

A Simple Grammar Defines Activating and Repressing cis-Regulatory Elements in Photoreceptors

“…In some cases, this dual function results from post-translational modifications (Méthot and Basler, 1999; Parker et al, 2011), while in others, binding sites for additional factors encode different activities at different cis-regulatory elements (Alexandre and Vincent, 2003; Martínez-Montañés et al, 2013; Pompeani et al, 2008; Rachmin et al, 2015; Sánchez-Tilló et al, 2015). We have shown here that variation in the number and affinity of binding sites for only a single TF is sufficient to encode activation versus repression.…”

“…Such dual-function TFs occur in organisms from bacteria to mammals (Martínez-Montañés et al, 2013; Pompeani et al, 2008; Liu et al, 2014; Rachmin et al, 2015; Sánchez-Tilló et al, 2015). Because activation and repression occur in the same cell, the response of a target gene to a TF must be encoded in cis-regulatory elements by the specific arrangement, number, affinity, and identity of TF binding sites (Levo and Segal, 2014).…”

Genomics of cellular proliferation under periodic stress

“…1B, differences were visible both among genes inhibiting growth and among genes promoting growth in high salt. For example, NBP2 is a negative regulator of the HOG pathway 20 and MOT3 is a transcriptional regulator having diverse functions during osmotic stress 21,22 . Deletion of either of these genes improved tolerance to steady 0.2M NaCl (condition S).…”