Cloning, genomic structure, and expression analysis of peroxiredoxin V from bay scallop Argopecten irradians

Peroxiredoxins (Prxs) constitute a superfamily of antioxidative proteins that play important roles in protecting organisms against damage from reactive oxygen species (ROS). In this study, the peroxiredoxin V gene from Argopecten irradians (Ai-PrxV) was isolated and characterized. The full-length Ai-PrxV cDNA consists of 1689 bp with a 567 bp open reading frame (ORF) that encodes 188 amino acids. Three putative polyadenylation consensus signals (AATAAA) were found in the 953 bp long 3'-UTR. The genomic length of the Ai-PrxV gene is 12575 bp, and it contains six exons and five introns. The gene structure is closely related to those of chordates but differs from those of arthropods. The 5' flanking region, which contains several putative transcription factor binding sites, was also analyzed. Quantitative real-time PCR analysis showed that the highest expression of the Ai-PrxV transcripts occurred in gill tissue. When challenged with the bacteria Vibrio anguillarum, the level of Ai-PrxV transcripts in hemocytes of bay scallops was up-regulated and reached the highest point at 15 h post-challenge. These results indicate that Ai-PrxV is a constitutive and inducible protein that plays an important role in the immune response against bacterial infection.