Regulated resource reallocation is transcriptionally hard wired into the yeast stress response

Abstract

Many organisms maintain generalized stress responses activated by adverse conditions. Although details vary, a common theme is the redirection of transcriptional and translational capacity away from growth-promoting genes and toward defense genes. Yet the precise roles of these coupled programs are difficult to dissect. Here we investigated Saccharomyces cerevisiae responding to salt as a model stressor. We used molecular, genomic, and single-cell microfluidic methods to examine the interplay between transcription factors Msn2 and Msn4 that induce stress-defense genes and Dot6 and Tod6 that transiently repress growth-promoting genes during stress. Surprisingly, loss of Dot6/Tod6 led to slower acclimation to salt, whereas loss of Msn2/4 produced faster growth during stress. This supports a model where transient repression of growth-promoting genes accelerates the Msn2/4 response, which is essential for acquisition of subsequent peroxide tolerance. Remarkably, we find that Msn2/4 regulate DOT6 mRNA production, influence Dot6 activation dynamics, and are required for full repression of growth-promoting genes. Thus, Msn2/4 directly regulate resource reallocation needed to mount their own response. We discuss broader implications for common stress responses across organisms. SYNOPSISThis study investigates how genes induced and repressed in the yeast Environmental Stress Response contribute to stress tolerance, growth rate, and resource allocation. The work uses molecular, genomic, and systems biology approaches to present new insights into eukaryotic responses to acute stress. HIGHLIGHTSO_LICells lacking stress-activated transcription factors have a faster post-stress growth rate C_LIO_LICells lacking repressors of growth-promoting genes have a slower post-stress growth rate C_LIO_LIStress-defense factors control the induction of growth-promoting gene repressors, thereby coordinating the resource re-allocation needed for the response C_LI