Response of a novel selenium-dependent glutathione peroxidase from thick shell mussel Mytilus coruscus exposed to lipopolysaccharide, copper and benzo[α]pyrene

Abstract Glutathione peroxidase (GPx) plays an important antioxidant role in cellular defense against environmental stress. In the present study, a novel selenium-dependent glutathione peroxidase termed Mc SeGPx firstly identified in thick shell mussel Mytilus coruscus. Mc SeGPx consists of 197 amino acid residues, characterized with one selenocysteine residue encoded by an opal stop codon TGA, one selenocysteine insertion sequence (SECIS) in the 3ʹ untranslated region (UTR), two active site motifs and one signature sequence motif. Mc SeGPx transcripts were constitutively expressed in all examined tissues, and were significantly induced in gills and digestive glands with the stimulations of lipopolysaccharide (LPS), copper (Cu) and benzo[ α ]pyrene (B[ α ]P). Additionally, rough increases in Mc SeGPx activity were detected in both tissues under the challenge of LPS, Cu and B[ α ]P. Collectively, these results suggested that Mc SeGPx affiliate to selenocysteine dependent GPx (SeGPx) family and might play an important role in mediating the environmental stressors and antioxidant response in M. coruscus .