|Ann M. Tarrant, Diane G. Franks, and Tim Verslycke, Gene expression in American lobster (Homarus americanus) with epizootic shell disease, Journal of Shellfish Research - special issue, submitted|
Epizootic shell disease (ESD) has been reported widely in American lobster (Homarus americanus) inSouthern New England. The appearance of irregular deep lesions, characteristic of ESD, has previously been associated with elevated levels of ecdysteroids and premature molting, but the underlying molecular and physiological changes associated with ESD remain poorly understood. Previously, we identified several genes, including arginine kinase and hemocyanin, that were differentially expressed in symptomatic ('diseased') versus asymptomatic (assumed 'healthy') lobsters and quantified their expression. In this study, we extend these findings and measured expression of a suite of 12 genes in tissues from 36 female lobsters of varying disease condition. In addition, molt stage was evaluated as a possible confounding factor in the expression of the selected genes. The expression of several genes changed significantly with disease stage. Arginine kinase expression significantly decreased in thoracic muscle of symptomatic lobsters. Ecdysteroid receptor expression was significantly elevated in both muscle and hepatopancreas of symptomatic lobsters. CYP45, a cytochrome P450 form that was previously shown to co-vary with ecdysteroid levels and to be inducible by some xenobiotics, showed significantly increased expression in hepatopancreas of symptomatic lobsters. Together these results demonstrate that the expression of several genes is altered in lobsters showing symptoms of ESD, even when accounting for variation in molt stage. Given the observed changes in ecdysteroid receptor, arginine kinase, and CYP45 expression, further investigations of the association, if any, between molting, muscular function and xenobiotic metabolism and ESD are warranted.