Meeting Abstract
Structural-proteins play a key role in extracellular matrix formation. Such an extracellular matrix is the mandible of our study organism C. quadricarinatus, a unique cuticular structure which is formed and partially mineralized during pre-molt as opposed to the rest of the cuticle which mineralizes at post-molt. The proteinaceous basis of this process is poorly known. In this study, a novel gene-family encoding Mandible Alanine Rich Structural (MARS) proteins is characterized and suggested to be involved in mandible formation. Our findings are based on a molt-related transcriptomic library originating from the mandible forming epithelia of C. quadricarinatus. This protein-family is characterized by an alanine, glutamine and glycine rich repetitive sequences, found also in other known structural proteins. In silico and In vitro spatial-temporal expression of all four MARS genes showed their expression in the mandible forming epithelia during pre-molt. Loss of function experiments using RNAi showed that dsRNA of a member of the family interfered with the transcript level of other members of the family and that silencing caused a dose dependent lethality. In addition, in animals injected with MARS dsRNA in parallel to molt-induction, structural deformities were detected in the incisor. Homologues MARS proteins with a high degree of conservation were found in other crustaceans. In this study, a newly found structural-genes family unique to crustaceans is characterized and suggested to have a role in mandible-formation in a decapod crustacean. Thus, providing for the first time insights into the proteinaceous basis of mandible-formation in crustaceans.
