SHECHTER , A; FREIMAN , A; TOM , M; YUDKOVSKI , Y; CHANG , A.S; CHANG , S.E; SAGI , A*; Ben-Gurion University ; Ben-Gurion University ; Israel Oceanographic and Limnological Research; Israel Oceanographic and Limnological Research; Univ of California, Bodega Marine Laboratory; Univ of California, Bodega Marine Laboratory; Ben-Gurion University ; : An inducible model for precise molt cycle-related polygenic differential expression in the crayfish Cherax quadricarinatus

The molt cycle in crustaceans is negatively regulated by the molt-inhibiting hormone (MIH) a neuropeptide which is secreted from the X-organ sinus gland complex (XO-SG). Initiation of the molting process and successful ecdysis are triggered by ecdysteroid hormones secreted from the thoracic Y-organ. These two events have been experimentally induced in the crayfish C. quadricarinatus by both XO-SG removal and direct administration of exogenous 20-hydroxyecdysone. Methodologies for precise follow up of the process were applied in both experimentally-induced and intact molt cycles. These include a unique noninvasive X-ray digital imaging of the gastroliths accompanied by measuring titers of circulating ecdysteroids. A 4700 clones Cherax cDNA microarray composed of transcripts from hepatopancreatic, epidermal and Y-organ origin was constructed to identify multi-genic expression patterns during the different experimentally-induced molt cycles. The transcript assemblage was cloned using the subtractive-suppression hybridization method. Labeled cDNAs representing hepatopancreatic transcript populations from experimentally-induced individuals are hybridized to the slides against similar populations from intact intermolt individuals to reveal differential expression of molt-related gene cluster patterns.