猪源乙型脑炎病毒HEN0701株全基因组的分子特征

Molecular characterization of complete genome of Japanese encephalitis virus HEN0701 strain isolated from swine

将乙型脑炎病毒HEN0701株基因组RNA分4段进行RT-PCR扩增,并克隆入pCRⅡ-Blunt-TOPO载体中,测定全长cDNA序列。以MapDraw软件分析了乙型脑炎病毒HEN0701株的基因组结构,并将病毒基因组分成2个非编码区和10个基因,比较了HEN0701株和11株乙型脑炎病毒在全基因组和各基因的核苷酸及推导氨基酸的同源性。以MEGA5软件绘制HEN0701株和11株病毒C、E、NS3、NS5基因的进化树。结果显示,HEN0701株全基因组为10 965 nt,包含一长10 299 nt的开放阅读框。在核苷酸水平,HEN0701株与GⅠ分离株的全基因组和各基因的同源性均高,而与GⅢ分离株则较低;而在氨基酸水平,HEN0701株与GⅠ分离株在多聚蛋白和各病毒蛋白的同源性和HEN0701株与GⅢ分离株的相近。进化分析显示,不同基因进化树的拓扑结构相近,12株病毒的C、E、NS3、NS5基因进化方向相同,GⅠ分离株和GⅢ分离株间C基因进化距离最近。

Four overlapping cDNA fragments from Japanese encephalitis virus（JEV） HEN0701 strain were cloned into pCR Ⅱ-Blunt-TOPO vector, followed by determination of complete genomic cDNA sequence. The complete genome of HEN0701 strain was 10 965 nucleotides in length, including a long open reading frame from 97th to 10395th nucleotide in the genome. Comparing to 6 strains of genotype Ⅰ （GⅠ ） JEV and 5 strains of GⅢ, HEN070] had high nucleotide sequence identity with G Ⅰstrains,but low nu- cleotide sequence identity with GⅢ strains in both complete genome and each gene. However, HEN0701 had high amino acid sequence identity with both G Ⅰ and GⅢ strains in both full polyprotein and each viral protein. Phylogenetic trees based on the C,E,NS3 and NS5 gene sequences of HEN0701 and 11 JEV strains were constructed with the software MEGA 5. Four phylogenetic trees had similar topology,indicating that the four genes from JEV had the similar evolutionary trend.