Analysis of porcine rotavirus A enterotoxin gene for structure-function relationship
Sharad Saurabh1, Shubhankar Sircar1, Jobin Jose Kattoor1, Souvik Ghosh2, N. Kobayashi3, Krisztian Banyai4, O.R. Vinod Kumar1, Ujjawal De1, Nihar Ranjan Sahoo1, Kuldeep Dhama1, Yashpal Singh Malik1,*
1Indian Council of Agricultural Research-Indian Veterinary Research Institute, Uttar Pradesh, India
2Department of Biomedical Sciences, One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Saint Kitts, West Indies
3Sapporo Medical University School of Medicine, Chuo-Ku, Sapporo, Japan
4Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungária krt. 21, Budapest 1143, Hungary
Correspondence to: Tel: +91-5812302777; Fax: +91-5812301757; E-mail: malikyps@ivri.res.in
Received: May 4, 2016; Revised: October 29, 2016; Accepted: November 23, 2016; Published online: January 4, 2017.
Abstract
Rotavirus (RV) infected piglets are presumed to be the latent sources of heterologous RV infection to humans and other animals. In RVs, non-structural protein 4 (NSP4) is the major virulence factor with pleiotropic properties. In this study, we analyzed nsp4 gene from porcine RVs, isolated from diarrheic and non-diarrheic cases, at different levels of protein folding to explore any correlation with their diarrhea inducing capabilities and evolution of nsp4 in porcine population. The full length nsp4 genes were amplified, cloned, sequenced and analyzed for antigenic epitopes, RotaC classification, homology, genetic relationship, modeling of NSP4 protein and prediction for post translational modification. Presence of RVs was seen in both diarrheic and non-diarrheic piglets. All nsp4 genes possessed E1 genotype. Comparison of primary, secondary, tertiary structure and prediction for post translational modifications of NSP4 from diarrheic and non-diarrheic piglets revealed no apparent differences. The sequence analysis indicated that nsp4 genes share multi-phyletic origin of evolution and exhibit species independent genetic diversity. This study also emphasized evolution of E9 nsp4 genotype from E1 genotype. The findings suggested that the diarrhea inducing capability of porcine RVs may not be exclusively linked to its enterotoxin gene.
Keywords: NSP4 gene, enterotoxin, evolution, porcine, rotavirus


© 2017 The Korean Society of Veterinary Science.