Transcriptional response to heat stress in the Antarctic bivalve Laternula elliptica

Our ability to predict animal responses to temperature changes is currently limited and more sensitive methods of identifying mechanisms, limits and thresholds are required. Antarctic marine ectotherms are excellent candidates for the study of warming seawater temperatures as they represent some of the most stenothermal species on Earth. They live within a narrow thermal window and exhibit reduced physiological capacities with small elevations in temperature. Whilst the physiological effects of elevated temperatures are well documented in these species, knowledge at the molecular level is scant and hence our understanding of the cellular response is still limited. To increase our knowledge in this area, a cDNA microarray consisting of 8448 clones was constructed to study the heat stress response of Laternula elliptica, an infaunal Antarctic bivalve. Eight clams were exposed to 12 h heat stress at 3 degrees C and their gene expression profiles were individually compared to a pooled reference of non heat shocked clams. Significant changes in the expression of 294 clones, representing 160 transcripts were observed. Of these, 33 were identified by sequence similarity searches and classified to a variety of cellular functions including protein turnover, folding and chaperoning, intracellular signalling and trafficking and cytoskeletal activity. These results suggest that antioxidant genes and genes involved in Ca2+ signalling and homeostasis represent potential biomarkers as to the physiological state of this species under thermal stress. (C) 2010 Elsevier B.V. All rights reserved.

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