Molecular characterization of the dual oxidase (LvDuox) gene from the pacific white shrimp Litopenaeus vannamei

The reactive oxygen species（ROS） generated by dual oxidases (Duox) play a role in innate immunity in many organisms. In this study, a 4,735 bp full-length cDNA of the Pacific white shrimp dual oxidase (LvDuox) gene was cloned; the sequence included an open reading frame of 4,497 bp, encoding a protein of 1,498 aa with a calculated mass of 173 kDa. Structural analysis revealed that LvDuox contains several domains. Homology analysis revealed that LvDuox exhibits 96.1%, 67.3% and 67.3% sequence identity with Marsupenaeus japonicas, Drosophila melanogaster and Acyrthosiphon pisum Duox, respectively. The mRNA transcripts of LvDuox were detected in all tested tissues. The mRNA expression of LvDuox was significantly induced in the midgut after Vibrio parahaemolyticus E1 (VPE1) stimulation. After the level of H2O2 in the midgut increased, expression of the superoxide dismutase and catalase genes in the midgut increased significantly. These results suggested that the LvDuox gene was upregulated in the midgut after the challenge by VPE1, and antioxidant genes were involved in the regulation of ROS in the shrimp midgut. LvDuox may therefore be a new target for intestinal disease research in the Pacific white shrimp.