Microarray gene expression profiles from temperature acclimated atrial, ventricular compact and spongy tissues of Pacific bluefin tuna Thunnus orientalis

In this study, we examined the transcriptomic responses to temperature acclimation (14oC, 20oC, and 25oC) in atrial and ventricular tissues of Pacific bluefin tuna (PBFT). A global gene expression analysis using a bluefin tuna-specific microarray indicated profound changes in expression of genes associated with energy metabolism, protein turnover, cellular stress response, oxidative stress and apoptosis. A principal component analysis revealed tissue-specific transcriptomic responses to temperature, with atrium at 25oC showing the greatest variation. Overall transcriptomic data suggests that PBFT can optimize cardiac function in the cold by acclimating to 14oC. Capacity to acclimate to colder temperatures potentially underlies this species ability to expand its vertical and horizontal thermal niche and migrate to colder oceans at high latitudes. In contrast, the cardiac phenotype of 25oC acclimated fish infers that PBFT hearts struggle to maintain cellular homeostasis and are subjected to programmed cell death. The goal of this study was to compare transcriptomic response to cold and warm temperature acclimations across cardiac tissues in Pacific bluefin tuna. Fish (n=4) were acclimated to 14C, 20C and 25C, and RNA was extracted from atrial, ventricular compact and spongy tissues. Experimental samples were hybridyzed against a reference pool that contained a mix of RNA from every sample.