Meeting Abstract

82.4  Sunday, Jan. 6  Novel chitin binding proteins with suggested role in organization of a crustacean cuticular chitinous extracellular matrix MITTELMAN , B.*; GLAZER , L.; WEIL, S.; GAFNI, O.; KHALAILA, I.; TOM, M.; DAVIDOV, G.; ZARIVACH, R.; SAGI, A.; Ben Gurion University of the Negev ; Ben Gurion University of the Negev ; Ben Gurion University of the Negev ; Ben Gurion University of the Negev ; Ben Gurion University of the Negev ; Israel Oceanographic and Limnological Research; Ben Gurion University of the Negev ; Ben Gurion University of the Negev ; Ben Gurion University of the Negev mittbiny@post.bgu.ac.il

Arthropod cuticles are multifunctional structures exhibiting a diverse set of mechanical properties. This diversity is partially attributed to interactions between a chitinous organic matrix and a plethora of proteins. Among these is a protein family containing three Chitin binding type 2 domains (ChtBD2), covering almost their entire length, found in cuticles across the arthropod phylum, and presumed to play a role in the organization of the chitinous matrix. Gastroliths are cuticular structures formed by the crayfish Cherax quadricarinatus during premolt, as transient calcium deposits. However, unlike the exoskeleton, gastroliths are relatively homogenous in composition, making them excellent research candidates for cuticular assembly. Two novel, strong chitin-binding proteins containing three ChtBD2 domains, were identified from C. quadricarinatus gastroliths. Their transcripts were fully sequenced based on RNA from the gastrolith-forming epithelium, and designated C. quadricarinatus gastrolith protein 30 and 35 (Cq-GAP30 and Cq-GAP35, respectively). 454-sequencing of C. quadricarinatus cuticular transcripts revealed additional expressed sequences from the same family. Furthermore, we recombinantly expressed both proteins, demonstrated their chitin-binding ability, and used them for production of polyclonal antibodies to examine the protein distribution pattern within the gastrolith matrix. Our study is aimed towards a better understanding of how chitin and proteins interact in arthropod cuticular structures.