HSP Antarctic molluscs Antarctic marine molluscs do have an HSP70 heat shock response 1

• Main Authors: Melody S. Clark, Keiron P. P. Fraser, Lloyd S. Peck
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; heat shock protein; stress; temperature; climate change 1 HSP Antarctic molluscs Summary; Nacella; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.323.1224; http://nora.nerc.ac.uk/3954/1/Mollusc_HSP.pdf

The success of any organism depends not only on niche adaptation, but also the ability to survive environmental perturbation from homeostasis, a situation generically described as stress. Although species-specific mechanisms to combat “stress ” have been described, the production of Heat Shock Proteins (HSPs), such as HSP70 is universally described across all taxa. Members of the HSP70 gene family comprising the constitutive (HSC70) and inducible (HSP70) members, plus GRP78 (Glucose-regulated protein 78kDa), a related HSP70 family member were cloned using degenerate PCR from two evolutionary divergent Antarctic marine molluscs (Laternula elliptica and Nacella concinna), a bivalve and gastropod respectively. The expression of the HSP70 family members was surveyed via Q-PCR after an acute two-hour heat shock experiment. Both species demonstrated significant up-regulation of HSP70 gene expression in response to increased temperatures. However, the temperature level at which these responses were induced varied with the species (+6-8°C for L. elliptica and +8-10°C for N. concinna) compared to their natural environmental temparture). L. elliptica also showed tissuespecific expression of the genes under study. Previous work on Antarctic fish has shown that they lack the classical heat shock response: with the inducible form of HSP70 being permanently expressed with expression not further induced under higher temperature regimes. This study shows that this is not the case for other Antarctic animals, with the two molluscs showing an inducible heat shock response, at a level probably set during their temperate evolutionary past. 2 HSP Antarctic molluscs