Molecular cloning and characterization of two genes encoding peroxiredoxins from freshwater bivalve Anodonta woodiana: Antioxidative effect and immune defense.

Members of Prx family function as an important players in host defense against oxidative stress, and modulate immune responses. In the current study, two complete Prx sequences were isolated from bivalve Anodonta woodiana and respectively named AwPrx4a and AwPrx4b. Regulative characterizations of AwPrx4a and AwPrx4b derived from perfluorooctanesulfonate (PFOS), perfluoroocanoic acid (PFOA), lipopolysaccharide (LPS) and polyinosinic:polycytidylic (Poly I:C) challenge in hepatopancreas, gill and hemocytes were measured by quantitative real-time PCR, respectively. The full-length cDNA of AwPrx4a had an open reading frame ORF of 588 bp encoding 196 amino acids. Two highly conserved Prxs signature motifs were observed in deduced amino acid sequence, one was FYPLDFTFACPTEI, and the other was GEVCPA. Complete cDNA sequence of AwPrx4b was comprised of a 5' untranslated region (UTR) of 120 nucleotides, a 426 bp ORF which was encoded 142 amino acids, and a long 3'-UTR of 412 nucleotides. Expressions of AwPrx4a and AwPrx4b showed a significant up-regulation pattern in groups at lower concentration treatment of PFOS and PFOA, a biphasic profile in groups with a higher concentration treatment. Compared with that of control group, expressions of AwPrx4a and AwPrx4b were significantly induced by LPS and Poly I:C treatment in the hepatopancreas, gill and hemocytes. These results indicate up-regulations of AwPrx4a and AwPrx4b expression are associated with eliminating oxidative stress derived from PFOS and PFOA administration as well as enhancing immune defense against LPS and Poly I:C challenge.