PRRSV分离株GP3蛋白ORF3基因克隆及序列分析

Cloning and Sequence Analysis of the GP3 Protein Encoding Gene ORF3 from PRRSV Clinical Isolate

为研究宁夏地区猪繁殖与呼吸综合征(PRRS)的流行规律,应用RT-PCR的方法从PRRSV分离株GP3蛋白中扩增出ORF3基因cDNA片段。结果显示,ORF3基因全长765 bp,编码254个氨基酸,与北美型毒株VR-2332的同源性达到85%以上,与欧洲型毒株LV的同源性低于60%,与国内近3年主要流行毒株JXA1、HEB1、HUB2亲缘性较近。对PRRSV分离株的亲水性分析表明,GP3蛋白的前57位氨基酸为疏水性信号肽序列;对PRRSV分离株GP3蛋白抗原表位分析表明,与国内外其他毒株抗原表位预测的结果基本一致,说明PRRSV分离株GP3蛋白具有与其他毒株相近的抗原特性。

In order to characterize the epidemic law of PRRS in Ningxia,the RT-PCR assay was used to amplify the cDNA fragment of ORF3 gene,a protein-encoding gene of GP3 protein,from the PRRSV clinical isolate.The results showed that the ORF3 gene of the PRRSV clinical isolate was 765 bp in length and encoded 254 amino acids.It had more than 85%homology with the North American type strain VR-2332 and less than 60%homology with the European type strain LV.The obtained PRRSV clinical isolate was genetically close to the strains of JXA1,HEB1 and HUB2 which were dominantly prevalent in China in recent 3 years.The analysis of the hydrophilicity of GP3 protein of the PRRSV isolate showed that its first 57 amino acids were hydrophobic signal peptide sequences.The analysis results of antigenic epitope prediction of GP3 protein of the PRRSV isolate were basically the same as those of some other domestic and foreign PRRSV strains,indicating that the GP3 protein of the PRRSV isolate in this study had similar antigenic properties to that of other strains.