Question

When activated in yeast cells, the MAP kinase kinase kinase, Ste11, can function to regulate mating, to respond to an increase in extracellular molarity, or respond to a condition of nitrogen starvation. Under conditions of high extracellular molarity, how does a yeast cell trigger activation of osmoresponsive genes, but not genes that are nitogen-responsive or mating partner-responsive?

Answer 1

ANSWER'

• Changes in the environment trigger a large common transcriptional response, called the environmental stress response, in budding yeast (Saccharomyces cerevisiae), which is characterized by re‐direction of resources from rapid proliferation to stress protection.
• In the environmental stress response, stress‐induced genes include genes for defense against reactive oxygen species and DNA damage, carbohydrate metabolism and energy generation functions, whereas most stress‐repressed genes have growth‐related functions, such as translation and ribosome biogenesis .
• environmental stress responses have common features, some aspects of the responses are unique to each individual stress. For instance, osmolyte‐synthesizing enzymes are specifically induced upon osmostress
• Transcriptional stress responses are sophisticated and fine‐tuned; the magnitude and duration of the response is proportional to the severity of the perturbation, and different perturbations result in distinct expression signatures