Single-particle view of stress-promoters induction dynamics: an interplay between MAPK signaling, chromatin and transcription factors

Abstract

Precise regulation of gene expression in response to environmental changes is crucial for cell survival, adaptation and proliferation. In eukaryotic cells, extracellular signal integration is often carried out by Mitogen-Activated Protein Kinases (MAPK). Despite a robust MAPK signaling activity, downstream gene expression can display a great variability between single cells. Using a live mRNA reporter, we monitored the dynamics of transcription in Saccharomyces cerevisiae upon hyper-osmotic shock. The transient activity of the MAPK Hog1 opens a temporal window where stressresponse genes can be activated. Here we show that the first minutes of Hog1 activity are essential to control the activation of a promoter. The chromatin repression on a locus slows down this transition and contributes to the variability in gene expression, while binding of transcription factors increases the level of transcription. However, soon after Hog1 activity peaks, negative regulators promote chromatin closure of the locus and transcription progressively stops.

Effect of Osmotic Stress on the Growth, Development and Pathogenicity of Setosphaeria turcica

“…Moreover, the role of HOG-MAPK in osmoregulation is conserved in many fungi, such as in Verticillium dahliae (Wang et al, 2016), B. oryzae (Turrà et al, 2014), U. virens (Zheng et al, 2016), and S. turcica (Li et al, 2016). In yeast, HOG-MAPK mediated osmoregulation by phosphorylating the activation site of Hog1 (peaking at 5 min), after which most Hog1 are transported to the nucleus to regulate transcription and the cell cycle, and after 30 min, glycerin accumulates in the cell to produce high osmotic pressure (Hao et al, 2007;Muzzey et al, 2009;Wosika and Pelet, 2020). In addition, in yeast, the greatest changes in the high osmolarity-regulated genes were observed within the first 40 min of treatment, with the maximal induction after 20 min of treatment (O' Rourke and Herskowitz, 2004).…”