Analysis of structure-function relationship in porcine rotavirus A enterotoxin gene

• DOI: 10.4142/jvs.2018.19.1.35
• Publication Date: 2018-02-05T08:56:43Z
• Authors: Sharad Saurabh; Shubhankar Sircar; Jobin J. Kattoor; Souvik Ghosh; Nobumichi Kobayashi; Krisztian Banyai; Obli R. VinodhKumar; Ujjwal K. De; Nihar R. Sahoo; Kuldeep Dhama; Yashpal S. Malik
• Keywords: Rotavirus; Swine Diseases; Protein Folding; 0303 health sciences; Swine; India; Viral Nonstructural Proteins; Rotavirus Infections; 3. Good health; Enterotoxins; Feces; 03 medical and health sciences; Prevalence; Animals; Original Article; Amino Acid Sequence; Sequence Alignment; Phylogeny; Glycoproteins; Toxins, Biological

Rotavirus (RV)-infected piglets are presumed to be latent sources of heterologous RV infection in humans and other animals. In RVs, non-structural protein 4 (NSP4) is the major virulence factor with pleiotropic properties. In this study, we analyzed the nsp4 gene from porcine RVs isolated from diarrheic and non-diarrheic cases at different levels of protein folding to explore correlations to diarrhea-inducing capabilities and evolution of nsp4 in the porcine population. Full-length nsp4 genes were amplified, cloned, sequenced, and then analyzed for antigenic epitopes, RotaC classification, homology, genetic relationship, modeling of NSP4 protein, and prediction of post-translational modification. RV presence was observed in both diarrheic and non-diarrheic piglets. All nsp4 genes possessed the E1 genotype. Comparison of primary, secondary, and tertiary structure and the prediction of post-translational modifications of NSP4 from diarrheic and non-diarrheic piglets revealed no apparent differences. Sequence analysis indicated that nsp4 genes have a multi-phyletic evolutionary origin and exhibit species independent genetic diversity. The results emphasize the evolution of the E9 nsp4 genotype from the E1 genotype and suggest that the diarrhea-inducing capability of porcine RVs may not be exclusively linked to its enterotoxin gene.