Data from: Stress response or beneficial temperature acclimation: transcriptomic signatures in Antarctic fish (Pachycara brachycephalum)

Research on the thermal biology of Antarctic marine organisms has increased awareness of their vulnerability to climate change, as a flipside of their adaptation to life in the permanent cold and their limited capacity to acclimate to variable temperatures. Here, we employed a species–specific microarray for the Antarctic eelpout, Pachycara brachycephalum to identify long-term shifts in gene expression after 2 months of acclimation to six temperatures between -1°C and 9°C. Changes in cellular processes comprised signalling, post-translational modification, sub–cellular organization, metabolic rearrangements and alterations in the transcription as well as translation machinery. The magnitude of responses was reflected in whole animal fitness parameters. An optimal growth performance at 3°C was paralleled by a minimum in responsive transcripts and altered expression levels indicative of a balanced steady state. The up–regulation of ribosomal proteins at 5°C and above was accompanied by differential protein degradation pathways. From 7°C upwards an incipient cellular stress response became visible through an increase of transcripts for heat shock proteins and an acute inflammatory response. A temperature–dependent energy deficit and a shift to autophagy became visible in the warmth by linking physiological performance to gene expression. Together, these patterns reflect specific cellular rearrangements as a consequence of either cold or warm acclimation and the progressive development of functional imbalances beyond the optimum temperature. The observed temperature–specific expression profiles reveal the molecular basis of thermal plasticity and refine the understanding of the outline and location of the thermal window in ectothermal species.