猪繁殖和呼吸综合征病毒ORF7基因的克隆与序列分析

根据猪繁殖和呼吸综合征病毒（PRRSV）已发表的核苷酸序列，设计了1对特异性引物P1／P2，用RT-PCR扩增了PRRSV福建毒株FJ-1和FJ-2的全长核衣壳蛋白基因（ORF7），将扩增产物连接到pUCm-T载体并转化大肠杆菌DH10B，提取阳性重组质粒进行序列测定与分析．结果表明：FJ-1和FJ-2毒株ORF7基因均为372bp，编码123个氨基酸，与美洲型参考毒株VR-2332及欧洲型参考毒株LV的核苷酸同源性分别为95．16％，94．35％和61．40％，60．65％，其推导的氨基酸同源性分别为95．93％，95．12％和56．49％，55．73％．研究表明，福建流行的FJ-1和FJ-2属于美洲型PRRSV毒株．

Amplification and Sequence Analysis of ORF7 Gene of Porcine Reproductive and Respiratory Syndrome Virus

Porcine Reproductive and Respiratory Syndrome Virus(PRRSV) strains FJ-1 and FJ-2 were isolated from a pig farm in Fujian province of China during an outbreak of PRRS.The full-length of ORF7 gene encoding the nucleocapsid protein(N) protein of FJ-1 and FJ-2 was amplified by RT-PCR with a pair of primers(P1/P2) and cloned into pUCm-T vector,and transformed to E.coli DH10B competent cell.The purified recombinants were subjected to sequencing and analysis.The ORF7 genes of FJ-1 and FJ-2 were both 372 bp and encoding 123 amino acids.They displayed 95.16 %,94.35 % and 61.40 %,60.65 % nucleotide identities to strains VR-2332(a reference strain of America) and LV(European genotype),respectively.The deduced amino acids of FJ-1 and FJ-2 showed 95.93 %,95.12 % and 56.49 %,55.73 % identities to strains VR-2332 and LV.The results shown here strongly suggested that PRRSV strains FJ-1 and FJ-2 belong to American genotype.