title: Molecular characterization and expression of the gene encoding aspartate aminotransferase from the Pacific oyster Crassostrea gigas exposed to environmental stressors.
abstract: A partial cDNA encoding cytosolic aspartate aminotransferase (AST) (EC 2.6.1.1) was isolated from a Crassostrea gigas digestive gland library. This sequence was used to design specific primers to amplify the AST genomic sequence. We obtained a complete gene, 5054 bp in length, encoding cytosolic AST and containing a 404 amino acid open reading frame. Phylogenetic analysis showed that C. gigas AST sequence constitutes a branch distinct from homologous sequences from other invertebrate groups. We also investigated AST mRNA expression in different tissues of oysters exposed to hydrocarbons, pesticides, hypoxia and hypo-salinity stress. The results showed that AST expression responds to hydrocarbon exposure, hypoxia and salinity stress, but not to pesticide exposure in an organ and time-specific manner. Use of AST as a potential molecular biomarker for monitoring of disturbed ecosystems is discussed.
authors.affiliation: Station Méditerranéenne de l'Environnement Littoral de Sète, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Boutet
authors.forename: Anne-Leila
authors.initials: AL
authors.lastname: Meistertzheim
authors.forename: Arnaud
authors.initials: A
authors.lastname: Tanguy
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Thébault
authors.forename: Dario
authors.initials: D
authors.lastname: Moraga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001219:Aspartate Aminotransferases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics*; D001483:Base Sequence; D015415:Biomarkers / Q000737:chemistry; D003001:Cloning, Molecular; D004781:Environmental Exposure / Q000009:adverse effects*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010125:Ostreidae / Q000201:enzymology* / Q000235:genetics*; D010802:Phylogeny; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D001219:Aspartate Aminotransferases