Meeting Abstract

15.7  Wednesday, Jan. 4  Novel molt-related hemocyanin family proteins from extracellular matrix of crustacean gastroliths GLAZER, Lilah*; WEIL, Simy; MITTELMAN, Benjamin; ROTH, Ziv; KHALAILA, Isam; TOM, Moshe; SAGI, Amir; Ben-Gurion University, Beer Sheva; Ben-Gurion University, Beer Sheva; Ben-Gurion University, Beer Sheva; Ben-Gurion University, Beer Sheva; Ben-Gurion University, Beer Sheva; Israel Oceanographic and Limnological Research, Haifa; Ben-Gurion University, Beer Sheva lilahg@bgu.ac.il

Other than oxygen carrying, the crustacean hemocyanin family of proteins is known to be involved in several aspects of the molt cycle, particularly in the synthesis and hardening of the new postmolt exoskeleton. Gastroliths are extracellular structures formed by the crayfish Cherax quadricarinatus during premolt, serving as transient calcium deposits. Like the crustacean exoskeleton, gastroliths are made of a chitinous organic matrix within which calcium carbonate (CaCO3) is deposited. Both the construction of the chitin scaffold and the precipitation of the CaCO3 involve proteins. Although gastroliths are cuticular elements, therefore sharing many characteristics with the exoskeleton, they are much simpler in structure, relatively homogenous in composition and lack pigmentation. In search for molt-related proteins involved in gastrolith formation we have isolated several novel proteins from the extracellular matrix of the gastrolith. Among those proteins is a prominent set of bands at ~75kDa, identified by mass spectrometry as several different subunits of hemocyanin and also cryptocyanin. These identifications were validated against pyro-sequencing results of C. quadricarinatus transcripts. In addition, the protein bands cross-reacted with anti-hemocyanin antibodies. We are studying the specific roles of the hemocyanin-family members found in extracellular matrix, using the gastrolith as a unique and relatively simple model for cuticular assembly.