A crayfish XXXX protein with putative mineralized exoskeletal chitinous matrix c properties.

@entity6445 @entity43350 @entity78 @entity4959 @entity460 @entity13258 @entity8679
UNASSIGNED: Some crustaceans possess exoskeletons that are reinforced with @entity4959 . In the crayfish Cherax quadricarinatus, the @entity13258 , which is part of the mandibular exoskeleton, contains an @entity8679 . As this layer resembles vertebrate enamel in composition and function, it offers an interesting example of convergent evolution. Unlike other parts of the crayfish exoskeleton, which is periodically shed and regenerated during the molt cycle, molar mineral deposition takes place during the pre-molt stage. The molar mineral composition transforms continuously from @entity43350 through amorphous @entity78 to amorphous @entity4959 and is mounted on chitin. The process of crayfish molar formation is entirely extracellularand presumably controlled by proteins, lipids, polysaccharides, low-molecular weight molecules and @entity460 salts. We have identified a novel molar protein termed Cq-M15 from C. quadricarinatus and cloned its transcript from the molar-forming epithelium. Its transcript and differential expression were confirmed by a next generation sequencing library. The predicted acidic pI of Cq-M15 suggests its possible involvement in mineral arrangement. Cq-M15 is expressed in several exoskeletal tissues at pre-molt and its silencing is lethal. Like other arthropod cuticular proteins, Cq-M15 possesses a chitin-binding Rebers-Riddiford domain, with a recombinant version of the protein found to bind chitin. Cq-M15 was also found to interact with @entity460 ions in a concentration dependent manner. This latter property might make Cq-M15 useful for bone and dental regenerative efforts. We suggest that, in molar, this protein might be involved in @entity78 and/or @entity6445 precipitation.
