Asia1型口蹄疫病毒第V群猪源和牛源毒株全基因组比较分析

Comparative Analysis of the Genomes of Foot-and-mouth Disease Virus Isolates from Porcine and Cattle Origin

摘要:

为了查明Asia1型FMDV第Ⅴ群猪源和牛源毒株的序列差异, 采用RT-PCR方法, 对Asia1型FMDV第Ⅴ群猪源分离毒株Asia1/HN/06的基因组全序列进行了扩增和测序, 并与第Ⅴ群牛源和猪源参考毒株基因组进行比较分析。结果表明, Asia1/HN/06毒株全基因组序列长约8236 nt [含38个A的poly(A)尾], 其中5'NCR长1116 nt, 前导蛋白(L)编码区长603 nt, 结构蛋白与非结构蛋白编码区的核苷酸序列为6990 nt, 3'NCR长93 nt, 3￠端是至少含有38个A的poly(A)尾巴。猪源毒株和牛源毒株的全基因比较分析表明, 属于第Ⅴ群, 全基因编码区核苷酸和氨基酸的同源性均为98.0%, 主要差别是猪源毒株Asia1/HN/06在细胞受体结合位点变为RDD和155位置的N变为S或D, 该群毒株3A更具有猪源毒株特征, 有4个特异性氨基酸变异。明确了Asia1型FMDV第Ⅴ群猪源和牛源毒株的序列差异, 为进一步利用反向遗传技术研究猪源和牛源毒株差异位点或基因在病毒表型变异中的作用奠定基础。

Abstract:

To investigate the differences between the genomes of foot and mouth viruses isolated from cattle and porcine origin, the complete genomes of two strains of Foot-and-mouth disease virus (FMDV), isolated from clinical tissue samples of pig and cattle, were amplified, sequenced and analyzed. The results showed that the genome sizes of the two viruses were 8236 nt in length, including 38-A poly (A) tail. The complete genomic nucleotide and amino acid identity between the two viruses were above 98.0%-99.4%. The phylogenetic tree based on the amino acid sequences of the entire ORF revealed that the Chinese isolates clustered together with the isolates from GroupⅤ. Our results revealed that the complete genome between the viruses from pig and cattle origin had higher homology and some differences that RGD sequence of the 1D-encoding region of isolates from cattle change into RDD, and the amino acid S change into N or D at +9 site in the isolates from pig. The 3A gene had the genetic characteristics from pig. The results lay a foundation for further study of role of the mutated genes in the molecular basis of fitness variations and changes in host cell tropism.