2株伪狂犬病毒变异株全基因组测序及主要保护性抗原氨基酸变异分析

Genome Sequencing of Two Pseudorabies Virus Variants and Amino Acid Mutation Analysis of Major Protective Antigen

为了解我国伪狂犬病毒(Pseudorabies virus,PRV)流行毒株遗传变异情况,对分离的2株PRV(HeNLH/2017和HeNZM/2017)全基因组序列进行测定,并利用生物信息学方法进一步分析其遗传进化特征和主要保护性抗原的遗传变异情况。基因组测序结果显示,分离的2株PRV基因组全长约为143 kb,GC含量约为73.8%。遗传进化分析显示,2株PRV毒株与Bartha株、我国早期流行毒株Ea和Fa株以及2011年以来流行的变异毒株(HeN1和HN1201)核苷酸同源性分别为95.28%~95.37%、98.70%~98.80%和98.90%~99.42%。系统进化树显示,2株PRV分离株均属于基因2.2亚型(Genotype 2.2),且与变异毒株遗传关系更近。PRV主要抗原gB、gC和gD蛋白的氨基酸变异分析显示,与Bartha株相比,2株PRV分离株以及我国其他PRV流行毒株均发生了广泛的氨基酸变异,且有gB 75SPG77的缺失、gC 63AAASTPA69和gD 278S/RPRP281的插入;与我国早期流行毒株Ea和Fa相比,2株PRV分离株以及我国2011年以来流行的变异毒株的gB、gC和gD蛋白氨基酸序列同源性很高,仅在个别位点发生了突变。

To investigate the genetic variations of pseudorabies virus(PRV)prevalent strains in China,we sequenced the full‑length genomes of two PRV(HeNLH/2017 and HeNZM/2017)isolated strains.Then,we conducted bioinformatics analyses,including phylogenetic analysis and amino acid mutation assay.The results showed that the length of genome was about 143 kb with a very high GC content of 73.8%.The whole genomic sequences displayed 95.28%—95.37%,98.70%—98.80%and 98.90%—99.42%nucleotide homology with those of Bartha,classical PRV strains(Ea and Fa)and PRV variants(HeN1 and HN1201),respectively.Phylogenetic analysis indicated that the two PRV strains belonged to Genotype 2.2 and were very close to the PRV variants.Furthermore,compared with the Bartha strain,extensive amino acid mutations were indentified in the major protective antigens of gB,gC and gD among the two PRV isolates and other PRV prevalent strains in China.They contained deletion of 75SPG77 for gB,insertion of 63AAASTPA69 for gC and 278S/RPRP281 for gD.However,the gB,gC and gD were still very conserved between PRV variants(including the two PRV isolates)and early prevalent strains(Ea and Fa),except that only a few amino acid substitutions were found.