SORTE, C.J.; HOFMANN, G.E.: Heat-shock protein expression in Nucella species of the Northeastern Pacific

Five species of Nucella, the dog whelk, are distributed across variable latitudes, with large areas of overlap, along the North American West Coast. In addition, within a rocky intertidal site, distribution of species differs with changing wave exposure and time of emersion. Due to their latitudinal and within-site distributions, Nucella species experience a large range of temperatures. This led us to question whether physiological processes such as the expression of heat-shock proteins (Hsps), which are initiated as a cellular protective mechanism against the heat-denaturation of proteins, play a role in determining the biogeography of these species. In order to explore this question, we measured several aspects of the heat-shock response (HSR). First, we quantified levels of Hsps in Nucella canaliculata, N. ostrina, and N. emarginata (Nc, No, and Ne, respectively) collected in Oregon (Nc and No) and California (Nc, No, and Ne). We then acclimated the whelks for one month at a common temperature and conducted heat-shock induction experiments to assess whether differences in the HSR are genetically hard-wired. Finally, we address whether other steps in the HSR may be modified between species. Our results help illustrate the relationship of cellular physiology adaptations to thermal regime and the biogeography of Nucella species.