title: Identification of three singular glycosyl hydrolase family 18 members from the oyster Crassostrea gigas: Structural characterization, phylogenetic analysis and gene expression.
abstract: Glycoside hydrolase family 18 (GH18) includes chitinases and non-enzymatic chitinase-like proteins (CLPs) with representatives among eukaryotes (animals and plants), prokaryotes and viruses. In Lophotrochozoa, one of the three clades of bilaterian animals, only three members (Cg-Clp1, Cg-Clp2 and Cg-Chit) have been reported from the bivalve mollusc Crassostrea gigas. Here, we describe the cloning and the characterization of two additional chitinases (Cg-Chit2 and Cg-Chit3) and a new CLP (Cg-Clp3) from this species. Cg-Chit2 presents an atypical C-terminal hydrophobic region acting probably as a GPI-anchor signal for plasma membrane attachment. On the contrary, Cg-Chit3 displays a C-terminal truncated structure leading to a possible sequestration in lysosomes. Phylogenetic analyses suggest that CLPs have appeared independently in the three main branches of bilaterian animals, as a result of convergent evolution. Gene expression profiles analyzed by quantitative RT-PCR support the involvement of Cg-Clp3 in embryonic development, adult oyster growth and tissue remodelling during metamorphosis and gonadal restructuring.
authors.affiliation: UMR M100 IFREMER-Université de Caen Basse-Normandie, IBFA Physiologie et Ecophysiologie des Mollusques Marins, 14032 Caen cedex, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Badariotti
authors.forename: Christophe
authors.initials: C
authors.lastname: Lelong
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Dubos
authors.forename: Pascal
authors.initials: P
authors.lastname: Favrel
mesh_terms: D000818:Animals; D049896:Crassostrea / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D011487:Protein Conformation; D013045:Species Specificity
chemical_list: D006026:Glycoside Hydrolases