7株新城疫病毒V基因遗传变异与病毒的基因分型

Genetic variation of V gene from seven isolates of Newcastle disease viruses and its relationship with virus genotype

测定了7株不同来源不同毒力新城疫病毒的V基因,并对它们的差异性和遗传进化关系进行了比对分析.结果显示:7株病毒V基因之间的核苷酸同源性为81.7%-99.7%,推导氨基酸残基的同源性为75.8%-99.6%;遗传进化分析显示,7株病毒分别处在3个不同的进化分支上,毒力相似的毒株聚类在同一进化分支上,而这与基于F基因的基因分型一致.由结果可推测,新城疫病毒V基因可能与F基因具有相似的遗传变异率,V基因也适合作为病毒基因分型分析的候选靶基因.

V protein is one of the accessory proteins of Newcastle disease viruses produced during the process of genome transcription by RNA editing.It is an interferon antagonist,which assists viruses to avoid host immune response,and may affect the pathogenicity and host range restriction of virus.In this study,nucleotide homology and phylogenetic analysis of V genes of seven isolates were performed.Comparison of V gene sequences showed nucleotide identity of 81.7%-99.7% and deduced amino acid identities of 75.8%-99.6% among the seven isolates.Phylogenetic analysis revealed that the isolates were divided into 3 different clusters,and strains with similar virulence were clustered together.The topology of phylogenetic tree based on the V genes was consistent with the tree based on fusion（F） genes of the viruses,which was used for genotype analysis.The results indicated that the nucleotide acids mutation rate of V genes resembled that of F genes,and V genes would also be suitable for genotype analysis of Newcastle disease viruses.