Molecular characterization and expression of the gene encoding aspartate aminotransferase from the Pacific oyster Crassostrea gigas exposed to environmental stressors

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology 2005, Vol.140 (1), p.69-78
• Main Authors: Boutet, Isabelle, Meistertzheim, Anne-Leila, Tanguy, Arnaud, Thébault, Marie-Thérèse, Moraga, Dario
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Aspartate aminotransferase; Aspartate Aminotransferases - biosynthesis; Aspartate Aminotransferases - chemistry; Aspartate Aminotransferases - genetics; Base Sequence; Biomarkers - chemistry; Cloning, Molecular; Crassostrea gigas; Environmental Exposure - adverse effects; Expression; Gene Expression Regulation, Enzymologic - physiology; Genomic sequence; Hydrocarbons; Hypoxia; In Vitro Techniques; Marine; Molecular Sequence Data; Ostreidae - enzymology; Ostreidae - genetics; Pesticides; Phylogeny; RNA, Messenger - biosynthesis; RNA, Messenger - genetics
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cca.2005.01.001

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.