Nonstructural protein gene-based molecular characterization of an attenuated goose parvovirus D strain
Published on: 2020-04-20
To characterize the non-structural (NS) protein gene of the vaccine of muscovy duck (Cairina moschata) origin Goose parvovirus (GPV) D strain, a pair of primers were designed by DNAStar software based on the published sequences of the MDGPV-PT strain published in GenBank. The homology, evolution of heredity, glycosylation sites, phosphorylation sites, B-cell epitopes, T-cell epitopes and secondary structure of the NS protein were analyzed analyzedusing using bioinformatics software. The full-length NS gene was amplified using PCR and cloned into a pMD18-T vector. Sequencing analysis demonstrated that the NS gene of the MDGPV-D strain comprised 1884 bp encoding 627 amino acids. The MDGPV-Dstrain NS gene had considerable similarity to that of MDPV (nt: 97.9-98.6%, aa: 97.6-98.2%). Three potential N-glycosylation sites and 27 phosphorylation sites were found to possibly exist in the MDGPV-D strain NS protein, possibly containing 11 B-cell epitopes, 13 CD8+ CTL epitopes and 10 CD4+ Th epitopes. Prediction of the secondary structure of the NS protein revealed that the alpha helix, random coil and beta angle accounted for 40.67%, 41.15%, and 4.63%, of the protein, respectively. Compared with the parental virulent PT strain, the attenuated vaccine strain D revealed that during the attenuation processes one common nucleotide change arose representing an amino acid substitution. The NS protein contained two amino acid substitutions, one being in the nucleoside triphosphate (NTP) binding motif at amino acid 338. The results of the present study provide a molecular basis for investigating attenuation mechanisms of MDGPV, and a useful reference for further studies of genetically engineered MDGPV vaccines.