宁夏地区猪生殖与呼吸综合征病毒ORF5基因的克隆及其变异分析

Cloning and variation analysis of ORF5 gene of porcine reproductive and respiratory syndrome virus of Ningxia isolates

参考GenBank中登录的猪生殖与呼吸综合征病毒（PRRSV）Jiangxi株和CH—la株的ORF5基N序列，设计并合成了1对引物，对宁夏回族自治区送检的18份PRRS阳性分离毒株进行RT—PCR扩增，获得约750bp的DNA片段，将其分别克隆入pMD18-T载体中，进行测序。应用DNAStar软件分析所测序列，并与ATCCVR-2332，BJ-4，RespPRRSMLV等毒株的ORF5序列进行比较，发现其核苷酸同源性为85．4％～89．0％，与CH—1a之间的核苷酸同源性为90．0％～98．2％，与欧洲代表株LV的核苷酸同源性为55．9％～56．6％。基因系统进化树分析表明，发生于宁夏回族自治区的PRRSV属于美洲型，与CH—1a遗传关系较近，归属同-基因亚型。

According to the ORF5 gene sequence of Jiangxi and CH la strains of porcine reproductive and respiratory syndrome virus （PRRSV） available in GenBank, one pair of primers was designed and synthesized for RT-PCR amplification ORF gene from 18 samples isolated from Ningxia Hui Autonomous Region. All of the amplified fragments of ORF5 genes were 750 bp. The corresponding DNA fragments were respectively cloned into pMD18-T vector and sequenced. The sequences of ORF5 genes were analysed using DNAStar software. Nuclear acid analysis indicated that the amplified ORF genes shared 85.40/00 -- 89.0 % homology with ATCC VR-2332, BJ-4 and RespPRRS MLV strains, 90.0 %--98.2 % homology with CH-la and 55. 9%-- 56. 60% homology with LV, respectively. The ORF5 gene phylogenetic tree showed that the PRRSV isolates from Ningxia Region were PRRSV American genotype and the same subtype with CH-la strain.