GxE Interactions in Stress Response Contribute Additively to a Genotype-Environment Interaction

The “cellular stress response is a general term in cell biology, covering a wide range of molecular changes that cells undergo in response to environmental stressors––including extremes of temperature, exposure to toxicants, and mechanical damage. The various processes involved in cellular stress responses serve the adaptive purpose of protecting a cell against unfavorable environmental conditions, both through short-term mechanisms that minimize acute damage to the cell’s overall integrity, and through longer-term mechanisms that provide the cell a measure of resiliency against similar adverse conditions.

Determining the genetic and molecular mechanisms that give rise to genotype-environment (GxE) interactions … is important for many areas of biology, including agriculture,

evolution, and medicine. To help advance knowledge regarding this topic, authors [see attached article] dissect, using yeast as a model, the genetic basis of an example of GxE interactions in which certain Saccharomyces cerevisiae cross-progeny show extremely poor growth specifically on ethanol at 37°C. This environment differs from the standard condition used for culturing budding yeast in both its carbon source (ethanol as opposed to glucose) and temperature (37°C as opposed to 30°C).

Authors provide evidence that poor growth on ethanol at 37°C is caused by a number of predominantly additive loci (i.e. equal contributions by genes from both parents) that individually exhibit GxE interactions with both carbon source and temperature. These loci show their largest effects when carbon source and temperature are simultaneously modified––indicating their effect magnitudes may be influenced by severity of the environmental stress. Consistent with this possibility, the authors cloned three causal genes and discovered that they encode functionally unrelated components of the stress response. These data suggest that polymorphisms in stress response can contribute additively to GxE interactions that vary in intensity across conditions, … in a stress level-dependent manner.

PLoS Genet 2o16; 12: e1006158

Addendum (or After-Thought), ….. if anyone wondered what THIS topic (in yeast, no less) has to do with ‘Gene-Environment Interactions’.

The Cellular Stress Response, and its associated complex multi-gene expression pathways, … undoubtedly play a role in environmental health and disease as the result of EXPOSURE to sufficient levels of environmental toxicants (noxious chemicals) that cause serious injury to cells. The cellular stress response will also participate clinically in (sufficiently) serious/damaging adverse drug reactions.

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