A gastrolith protein serving a dual role in the formation of an amorphous mineral containing extracellular matrix

摘要: Despite the proclamation of Lowenstam and Weiner that crustaceans are “champions mineral mobilization deposition animal kingdom,” relatively few proteins from two main calcification sites in these animals, i.e., exoskeleton transient calcium storage organs, have been identified, sequenced, their roles elucidated. Here, a 65-kDa protein (GAP 65) gastrolith crayfish, Cherax quadricarinatus, is fully characterized its function mineralization amorphous carbonate (ACC) extracellular matrix demonstrated. GAP 65 negatively charged glycoprotein possesses three predicted domains: chitin-binding domain 2, low-density lipoprotein receptor class A domain, polysaccharide deacetylase domain. Expression was localized to columnar epithelial cells disk during premolt. In vivo administration dsRNA resulted significant reduction transcript levels disk. Such gene silencing also caused dramatic structural morphological deformities chitinous-ACC structure. ACC deposited gastroliths appeared be sparsely packed with large elongated cavities compared normal gastrolith, where densely compacted. spherules significantly larger than normal. 65, moreover, inhibited crystallization vitro stabilized synthetic ACC. Thus, first shown dual function, involved both formation biomineralization.