Gene expression profile, protein production, and functions of cryptocyanin during the crustacean molt cycle

Abstract

Orchestration of the synthesis of a new exoskeleton and degradation of the old exoskeleton during molting requires precise programming. We have studied expression patterns of members of the hemocyanin gene family, hemocyanin, cryptocyanin, and phenoloxidase, in Cancer magister to better understand the molecular basis of the complex regulation and physiological transformations that occur during molting. Results of electrophoresis, immunohistology, in situ hybridization, and real-time qPCR studies on animals sampled across their molt cycles have established that cryptocyanin functions in forming the new exoskeleton. The protein is synthesized in the hepatopancreas, transported in the hemolymph and moved across the epithelium to the new exoskeleton. The presence of cryptocyanin and hemocyanin in oocytes, embryos and zoeas of multiple species indicates that cryptocyanin is available from the earliest onset of cuticle formation in development. Analysis by cDNA microarray supports our studies on hemolymph proteins hemocyanin and cryptocyanin, indicating that these genes are independently regulated. The cryptocyanin transcriptional patterns that change as a function of the molt cycle have also been reported in other species. Cryptocyanin, analogous to vertebrate serum albumin, may also participate as a carrier protein for hormones, divalent cations, or other molecules, as an effector of osmotic balance, and as part of the immune defense during premolt and early postmolt.