猪繁殖与呼吸综合征病毒强弱毒株全基因序列比对分析

为了解猪繁殖与呼吸综合病毒（PRRSV）致弱的分子学基础，对PRRSV JXA1株第5代（强毒）与第86代毒株（致弱毒）进行全基因组测序，将JXA1原始毒株和JXA1致弱毒株与其他2对PRRSV原始毒株/弱毒疫苗株进行基因序列比对分析。结果显示，这3对毒株（1对JXA1原始毒株/致弱毒株、2对PRRSV原始毒株/弱毒疫苗株）中结构蛋白的氨基酸突变率较高，表明毒力的改变与结构蛋白的改变关系更大；将JXA1株与JXA1-86株序列比对分析，发现编码Nsp5、Nsp6、Nsp8、Nsp12、M、N蛋白的氨基酸未发生变化，表明JXA1株毒力的降低可能与这些蛋白无关；将各代次PRRSV序列比对分析，发现在第70代到第86代序列之间，ORF1a中A₉₂₈V、I₁₁₅₅M、E₁₆₂₉D，GP2中I₁₁₈V，GP3中H₇₉N，GP4中I₁₂₄V，GP5中K₅₉N发生了改变，表明其毒力的减弱可能与以上几处变异有关。

Complete Genome Comparison and Analysis between Porcine Reproductive and Respiratory Syndrome Virus Parental and Its Attenuated Strains

To study the attenuation molecular basis of porcine reproductive and respiratory syndrome virus (PRRSV),whole genomes of PRRSV JXA1-5 (parental strain) and JXA1-86 (attenuated strain) were sequenced,compared and analyzed.And genomic sequences of JXA1/JXA1-86 were compared with the other two pairs of virulent parental/attenuated vaccine strains.The results showed that there was higher amino acid mutation rate in structural proteins among the three pairs of strains indicating that PRRSV JXA1 strain virulence changes were more related to structure proteins variations.Compared with JXA1,the amino acids encoding Nsp5,Nsp6,Nsp8,Nsp12,M and N proteins of JXA1-86 strain did not change,suggesting that virulence attenuating might not be relevant to those proteins.The genomic sequences of each generation PRRSV sequence were compared and analyzed,and the results showed that the variations among A₉₂₈V,I₁₁₅₅M,E₁₆₂₉D in ORF1a,I₁₁₈V in GP2,H₇₉N in GP3,I₁₂₄V in GP4 and K₅₉N in GP5 between 70th and 86th generations were found,which turned out that virulence attenuating might be associate with those variations.