中文摘要：

从猪繁殖与呼吸综合症病毒（PRRSV）河南分离株（HN07-1、HN07-2）的细胞培养物中提取RNA,根据参考株IAF-exp91 N蛋白基因序列设计出2对引物,成功克隆出ORF7全长基因,并连接至pMD-19T载体。基因测序结果表明,2株PRRSV河南分离株ORF7基因序列完全相同;该序列与HB-4（hs）同源性为100%,与标准美洲株VR-2332和我国早期分离的BJ-4株同源性为93.8%。将该基因亚克隆到原核表达载体pGEX-6p-1后,转化大肠杆菌BL21,IPTG诱导表达并对表达条件进行优化。SDS-PAGE和Western-blot结果表明,成功表达了约40 kD的融合蛋白;使用1.0 mmol/L的IPTG在2×YT培养基中诱导8 h可获得最大表达量。

英文摘要：

Total RNA was extracted from the cell cultures of two Henan strains of porcine reproductive and respiration syndrome virus（PRRSV）,HN07-1 and HN07-2,and the ORF7 gene of PRRSV was amplified by RT-PCR using specific primers designed according to the sequence of the nucleocapsid protein（N） gene of IAF-exp91.The PCR products were connected into pMD-19T vector,cloned and sequenced.The results showed that the ORF7 genes of the two strains were same to each other,and the homology of ORF7 gene with HB-4（hs）,VR-2332,and BJ-4 was 100%,93.8%,and 93.8%,respectively.A prokaryotic expression vector pGEX-6p-1 containing ORF7 gene was constructed,transformed into E.coli BL21 and induced with IPTG.SDS-PAGE and Western-blot confirmed that the recombinant protein of 40kD was successfully expressed in E.coli BL21.