Objective: The ovine rotavirus strain NT isolated from diarrhea lamb in China was considered as a promising vaccine strain. Based on the VP1 gene was one of the important structural proteins of rotavirus, we studied on the evolutional characteristics of VP1.
Methods: According to the published conservative sequences of VP1 genes, we designed a pair of specific primers for cloning and sequencing of VP1 gene.
Results: Sequencing result showed that the VP1 gene was 3,302 bp in length and the deduced protein was 1,088 aa. Comparison of amino acid sequences revealed that the ORV-NT shared 77.3% - 98.4% similarities with other group A rotaviruses. Furthermore, sequence alignment analysis manifested that amino acid variations mainly occurred in the non-functional regions of VP1 protein. Phylogenetic analysis of VP1 protein showed that the OVR-NT was grouped in the bovine rotavirus clusters, indicating a closer relationship between them. Evolutionary distance of nucleotide sequence and amino acid sequence among VP1 genes of different rotaviruses were calculated, respectively. Analysis of synonymous mutation rate and Non-synonymous mutation rate demonstrated that synonymous substitution was the major pattern of variation in the process of evolution.
Conclusion: This was the first report on sequencing and evolutionary distance analysis of VP1 gene of ORV-NT.