伪狂犬病病毒FJ-2015株主要免疫原基因的遗传进化分析

Genetic analysis of major immunogen genes of the variant pseudorabies virus strain FJ-2015

为了解伪狂犬病病毒(PRV)变异株主要免疫原相关基因的序列遗传特征,本研究对PRV FJ-2015株g B、g C和g D基因进行克隆和测序分析。结果显示,FJ-2015株3个主要免疫原基因推导氨基酸序列与2012年以来国内新分离PRV变异株同源性较高,分别为99.7%~100%、99.6%~100%和98.5%~99.8%;而与国外分离株氨基酸同源性较低,分别为96.9%~97.5%、93.1%~93.3%和97.3%~98.8%,其中与疫苗株Bartha-K61同源性最低,为96.9%、93.1%和97.3%;氨基酸比对显示,与经典病毒株相比,该病毒株发生多个位点的一致性替换、插入或缺失,并处于重要的抗原表位区;遗传进化关系表明,该病毒株g B基因遗传演化与分离时间和分离国家相关,g C基因显示遗传多样性,而g D基因具有一定的福建区域性遗传演化关系。以上结果表明,PRV FJ-2015属于PRV变异株,与其它分离株存在一定的遗传差异。本研究丰富了猪PRV流行的分子特征。

To understand the genetic characteristics of the main immunogen related genes of variant pseudorabies virus （PRV）, the gB, gC and gD genes of the PRV FJ-2015 strain were cloned and sequenced in this study. The results demonstrated that the amino acid sequences of the 3 main immunogen genes of the PRV FJ-2015 strain shared high homologies with that of variant PRV strains isolated since 2012, and the homologies were 99.7%-100%, 99.6%-100% and 98.5%-99.8%, respectively. However, the gB, gC and gD genes of the PRV FJ-2015 strain shared lower homologies with that of the foreign PRV strains, the homologies were 96.9%-97.5%, 93.1%-93.3% and 97.3%-98.8%, respectively, and the lowest homologies were shared with Bartha-K61 vaccine strain, which were 96.9%, 93.1% and 97.3%, respectively. The amino acid comparison showed that the multiple variations took place on the PRV FJ-2015 strain compared with the classical PRV strains, including substitutions, insertions and/or deletions, some of which were located in epitopes. Phylogenetic analysis based on these gene sequences indicated that the gB gene differed significantly depending upon the isolation countries and isolated times, the gC gene showed genetic diversity and the gD gene was unique in the Fujian region. The above results indicated that PRV FJ-2015 strain was a variant pseudorabies virus which had certain genetic differences from other PRV isolate strains. This study enrichs the molecular epidemiology of PRV.