Insight into post-transcriptional gene regulation: stress-responsive microRNAs and their role in the environmental stress survival of tolerant animals.

Living animals are constantly faced with various environmental stresses that challenge normal life, including: oxygen limitation, very low or high temperature, as well as restriction of water and food. It has been well established that in response to these stresses, tolerant organisms regularly respond with a distinct suite of cellular modifications that involve transcriptional, translational and post-translational modification. In recent years, a new mechanism of rapid and reversible transcriptome regulation, via the action of non-coding RNA molecules, has emerged into post-transcriptional regulation and has since been shown to be part of the survival response. However, these RNA-based mechanisms by which tolerant organisms respond to stressed conditions are not well understood. Recent studies have begun to show that non-coding RNAs control gene expression and translation of mRNA to protein, and can also have regulatory influence over major cellular processes. For example, select microRNAs have been shown to have regulatory influence over the cell cycle, apoptosis, signal transduction, muscle atrophy and fatty acid metabolism during periods of environmental stress. As we are on the verge of dissecting the roles of non-coding RNA in environmental stress adaptation, this Commentary summarizes the hallmark alterations in microRNA expression that facilitate stress survival.