Identification of differentially expressed genes in the hydrothermal vent shrimp Rimicaris exoculata exposed to heat stress.

The deep-sea vent shrimp Rimicaris exoculata dominates the vagile megafauna at most vent sites along the Mid-Atlantic Ridge. This shrimp swarms around the hot end of the hydrothermal biotope where temperature can exceed its critical maximal temperature (33-38.5 ± 2°C). It may therefore be subjected to a thermal regime that is assumed to be stressful for animals. In this study, we used a global transcriptomic approach by constructing suppression subtractive hybridization cDNA libraries in order to identify specific up- and down-regulated genes in R. exoculata exposed to a severe heat stress (1h at 30°C). A total of 218 sequences representing potentially highly expressed genes in thermally stressed shrimp were obtained. Expression of 11 genes involved in various cell functions was quantified in control and heat shocked specimens using real-time PCR. Differential expression was observed for some specific genes such as mannose receptor C1, metalloprotease, histone H1, and hemocyanin with a strong up-regulation of several genes encoding heat shock proteins. These results suggest that R. exoculata is affected at both cellular and molecular levels by sustained exposure at 30°C. The sequenced ESTs presented here will provide an excellent basis for future thermal stress studies on deep-sea vent fauna.