高致病性猪繁殖与呼吸综合征病毒山西分离株的鉴定及部分Nsp2基因序列分析

本研究采集山西省不同地区的发病猪脏器组织与血液样品,采用特异性 RT-PCR方法检测高致病性猪繁殖与呼吸综合征(porcine reproductive and respiratory syndrome,PRRS)样品16份,应用设计的特异性引物扩增出Nsp2基因序列,利用DNAStar生物信息学分析软件,对获得的序列与国外代表毒株VR-2332、国内代表毒株CH-1a、BJ-4、HB-1及PRRSV变异毒株HuN4和JXA1的序列进行了比较,绘制系统发生树。氨基酸序列比较分析发现山西省流行毒株同源性分别在69.8%~71.7%、85.3%~87.9%、68.7%~70.6%、91.7%~94.3%、94.3%~98.5%、95.1%~98.9%。所获得的16株病毒之间的同源性在90.9%~100%之间。研究结果发现所获得的序列同源性与国内近几年流行的PRRSV的变异毒株HuN4和JXA1毒株的序列同源性最高,分别在94.3%~98.5%与95.1%~98.9%之间,Nsp2 基因缺失位置一致,其Nsp2均有2个部位出现了缺失,即Nsp2基因分别为编码1个氨基酸的3个核苷酸的缺失和编码29个氨基酸的连续87个核苷酸的缺失,结果表明,山西省目前流行PRRSV的变异毒株与国内流行株属于同一分支。

Analysis of Sequence of Nsp2 Gene Isolated from Highly Pathogenic PRRSV Strains in Shanxi

In this study,total RNA was extracted from tissues and serum in incident swines from different regions of Shanxi.The highly pathogenic PRRSV of 16 samples were positive by RT-PCR.The gene sequence of Nsp2 was amplified using the specific primers.The analysis of gene sequences by DNAStar and bioinfomatic software showed that the amino acids sequence of Nsp2 shared 69.8% to 71.7%,85.3% to 87.9%,68.7% to 70.6%,91.7% to 94.3%,94.3% to 98.5%,95.1% to 98.9% similarity with VR-2332,CH-1a,BJ-4,HB-1,HuN4 and JXA1 strains respectively,following the comparison of sequences and homologue analysis.The results also showed that Nsp2 from Shanxi strains lacked amino acids at 2 locations,and one location was 1 amino acid and another was continuous 29 amino acids.It suggested that the PRRSV mutant strains in Shanxi belonged to the same branch as the domestic epidemic strains.