羊口疮病毒疫苗株与野毒株VIL-10基因的比较分析

试验旨在比较分析羊口疮病毒（orf virus，ORFV）VIL-10基因在疫苗株和野毒株之间的差异特征。参照GenBank中公布的ORFV NZ2株的VIL-10基因序列设计并合成1对特异性引物，分别以疫苗株和野毒株提取的基因组DNA为模板，采用PCR方法扩增ORFV的VIL-10基因全序列并进行测序，应用生物信息学相关软件分析基因的核苷酸、氨基酸变异情况及蛋白结构。结果显示，本试验测定的疫苗株和野毒株VIL-10基因核苷酸序列同源性为94.4%，差异主要是单个碱基的突变，其中疫苗株在132~134 bp核苷酸序列出现缺失；氨基酸序列同源性为92.5%，出现了15个氨基酸位点的突变，其中疫苗株第42位氨基酸天冬酰胺出现缺失；蛋白质在一级结构及理化性质、二级结构、三级结构、抗原表位参数及有无信号肽之间均存在一定程度的差异，而疫苗株和野毒株编码的蛋白质均无跨膜结构域。系统进化树分析结果表明，本试验测定的野毒株与疫苗株属于不同分支，遗传关系较远。研究结果提示，野毒株与疫苗株的VIL-10基因发生较明显的变异，这些变异可能与ORFV疫苗株的毒力致弱有关。

Comparative Analysis of VIL-10 Gene Between the Vaccine and Wild Strains of Orf Virus

To analyze the different characteristics between VIL-10 gene from the vaccine and wild strains of orf virus (ORFV),a pair of specific primers was designed according to ORFV NZ2 strain VIL-10 gene sequence reported in GenBank.The genomic DNA was taken as templates extracted from the vaccine and wild strains of ORFV.The full lengths of VIL-10 gene were obtained by PCR and then sequenced.The variation of nucleic acids,amino acids and protein structures were predicted and analyzed using bioinformatics software.The results showed that VIL-10 gene from ORFV vaccine strain and wild strain shared 94.4% identity at nucleotide level and the main difference was a single base mutation,deletion in the nucleotide sequence which occurred at 132 to 134 bp.92.5% identity at amino acid level and a mutation of 15 amino acid sites occurred,of which the asparagine was missing at 42 amino acid position.There were some differences in primary structure and physical and chemical properties of protein,secondary structure,tertiary structure,physicochemical properties,epitope parameters and the presence or absence of signal peptide.However,no transmembrane domains were identified both in the vaccine and virulent strains of ORFV.Phylogenetic analysis revealed that the wild strain and the vaccine strain belonged to different branches and the genetic relationship was far away.The results suggested that the VIL-10 gene of wild virus strains and vaccine strains had obvious mutations,and these mutations might be related to the virulence of the vaccine strains.