CHARACTERIZATION OF Mx GENES RESPONSES FOR NODAVIRUS INFECTION IN ORANGE-SPOTTED GROUPER (Epinephelus coioides)

Yuan-Ning Wang, Young-Mao Chen, and Tzong-Yueh Chen*

Department of Biotechnology and Bioindustry Sciences, Institute of Biotechnology, Translational Center for Marine Biotechnology, Agriculture Biotechnology Research Center, National Cheng Kung University, Tainan 70101, Taiwan
ibcty@mail.ncku.edu.tw

Groupers are the most important fish species in Asia aquaculture, but nervous necrosis virus (NNV) infection has been responsible for disastrous financial losses. During virus infection, virus infected grouper will induce many immune gene and antiviral protein expression, Mx protein is one of them. Mx proteins are main components of the antiviral innate immune response mediated by type I interferon (IFN). Therefore, we investigate the characteristics of three Mx genes in orange-spotted grouper response to NNV.

osgMx1, osgMx2, and osgMx3 are cloned from orange-spotted grouper, and they are containing conserved GTPase binding domain and leucine zipper domain. Three Mx gene regulations in response to the NNV infection was analysis by real-time PCR and luciferase assay. Gene expression of osgMx1 was about 132 times in the third day against to control group while osgMx2 showed 1.4 times in 12 hours, and osgMx3 showed 24.4 times in the third day. The luciferase assay results are similar to transcription activity. Both gene expression and promoter activity of osgMx1 showed the highest fold change. It suggests a differential modulation of each Mx gene transcription over the immune response to NNV. Altogether, the results have provided new insight of viral disease prevention in grouper aquaculture industry.