Ventricular transcriptomic changes induced by cold‐acclimation in the painted turtle suggests epigenetic‐mediated transcriptional remodeling

Abstract

Ectothermic vertebrates living at extreme latitudes are often forced to endure extended periods with their body temperatures at or just above the freezing point of water. Cold temperatures impose a number of physiological and biochemical challenges directly related to the thermodynamic effects on biological matter, including metabolic enzyme kinetics and even the physical properties of blood. The painted turtle, Chrysemys picta, is a pond turtle that can experience temperatures just above freezing for 3–5 months as adults and can tolerate freezing or even subzero temperatures as hatchlings. In the present study, we characterized how cold acclimation to 3°C affected the ventricular transcriptome in both adult and hatchling turtles. Because hatchlings must tolerate subzero temperatures when they overwinter in their nest, we sought to determine if they might also exhibit a unique gene expression pattern related to possible cryoprotective mechanisms. Despite differences in life history, adults and hatchlings responded similarly to cold acclimation at the transcriptomic level; out of the 1304 genes that were differentially expressed due to temperature, 1272 showed similar expression patterns in adults and hatchlings, the majority of which were upregulated. In adults and hatchlings combined, 776 genes were upregulated at 3°C, 550 genes were downregulated, of which 22 fell into both categories due to development‐specific expression patterns. Of these upregulated genes, 51 encoded for transcription factors, 27 for histone modification proteins, and 26 for mRNA processing and translational regulation enzymes. These results suggest that the ventricle actively remodels chromatin structure and modulates both gene expression and mRNA processing in response to cold acclimation.Support or Funding InformationThis work was supported by NSF CAREER grant 1253939 awarded to DEWThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.