Molecular Characteristics Analysis of D-strain Vaccine Virus of Muscovy Duck-origin Goose Parvovirus NS Protein Epitopes

To analyze the non-structural protein NS gene of vaccine muscovy duck (Cairina moschata) origin Goose parvovirus (GPV) D strain,apair of primers were designed by DNAStar software based on the published sequences of MDGPV-PT strain from GenBank. We examed the homology,heredity evolution,N-glycosylation sites,phosphorylation sites,B cell epitopes,T cell epitopes and their secondary structure of NS protein with bioinformatics software.The full length NS gene was amplified by PCR and cloned into pMD18-T vector. Sequencing demonstrated that the NS gene of MDGPV-D strain contained 1 884bps,encoding 627amino acids (GenBank number : JF926696) .The MDGPV-Dstrain NS gene was highly similar to that of MDPV (nt:97.9%98.6%,aa : 97.6% -98.2%) .It was also shown that there were 3 potential N-glycosylation sites and 27 phosphorylation sites existed in MDGPV-D strain NS protein,and 11Bcell epitopes,13CD8 + CTL epitopes and 10CD4 + Th epitopes as well.Then the prediction of secondary structure of NS protein showed that alpha helix,random coil and beta angle account for 40.67%,41.15% and 4.63% respectively.Comparison of the parental virulent strain PT with its attenuated vaccine strain D revealed two site-specific mutagenesis:one was in the nucleoside triphosphate (NTP) binding motif at amino acid 338,and the other in a CD4 + Th epitope at amino acid 225.These studies has provided a molecular basis for investigating attenuation mechanisms of MDGPV,and benefitted for further researches on genetically engineered MDGPV vaccines.