Featured event

Eukaryotic ribosome (80S, from Baker's yeast).

Qbio Seminar Series-Elisha Ho

Event Details

When: April 6, 2016, 2:00 PM

Location: 3rd Floor Orchard View Room , Discovery Building

Contact: 608-316-4401, hstampfli@wisc.edu

Elisha Ho

Elisha Ho
Genetics & Biotechnology
UW-Madison

Stress-dependent transcriptome changes serve to reallocate translational capacity during stress acclimation

Proper response to environmental stress is pivotal for cells to survive and adapt to constantly changing environments. Activation of stress defense systems is often coupled with arrest of growth and cell cycle progression. The transcriptomic response of Saccharomyces cerevisiae to stress includes a common stress transcriptomic change called the environment stress response (ESR). The ESR includes induced expression of ~ 300 genes involved in stress defense andreduced expression of ~ 600 genes required for active growth, namely genes encoding ribosomal proteins and other translation machinery. There has been a debate if activation of the ESR, and in particular reduced expression of growth-promoting ESR genes, is an active response to stress or is merely an indirect byproduct of reduced growth and cell-cycle progression. Since stress responses are generally correlated with growth and division arrest, it is hard to deconvolute responses triggered directly by stress versus indirectly by growth reduction. Here, we decouple the response to external stress and growth control by following transcriptomic and proteomic changes of arrested cells upon stresses. Our results show that activation of the ESR, including repression of growth-promoting genes, is not associated with cell-cycle phase and is independent of growth arrest. Instead, arrested cells exposed to stress actively induce the ESR, even though they are no longer making significant biomass – this indicates that reduced expression of growth-promoting genes is not necessarily related to growth control. We are using mathematical modeling of transcriptome and proteome changes, along with polysome profiling to measured global translation rates, to understand the function of transcriptome changes under different conditions. Our results suggest that differences in transcript abundance during steady-state growth serve to set the levels of protein production required for a given growth rate, whereas changes in transcript levels during active stress help to reallocate translational machinery during acclimation.
Co-authors: Evgenia Shishkova , Joshua Coon, Audrey Gasch at Department of Chemistry and Genetics, UW-Madison

All QBio sponsored talks take place on Wednesdays at 2:00 p.m. in the 3rd floor Orchard View room of the Discovery Building. Talks are open to the public. Access to the room is via the elevator behind Aldo’s Cafe in the Northeast corner of the building.