登革1型病毒广州分离株全长E基因序列测定与分析

目的对两株登革1型病毒广州分离株(DV1-GZ01/03、DV1-GZ02/03)E基因进行序列测定及分析,了解此次分离的登革病毒流行株的可能来源及其生物学特性。方法应用RT-PCR扩增两分离株E基因,克隆到pGEM-T载体进行序列测定,应用计算机软件与国内外参考株及流行株进行同源性分析,绘制系统进化树。并作毒株感染细胞及乳鼠毒力试验。结果两分离株全长E基因为1 485 bp,与登革1型Austria/83株的同源性最高,核苷酸同源性均达96.6%,氨基酸同源性分别达97.4%、97.8%;与登革1型GD23/95株次之。构建的系统进化树将19株登革1型病毒分为3个基因群。两分离株与Austria/83、GD23/95同属于基因型Ⅳ型,在同一进化分支内。两分离株颅内接种乳鼠均发病,但发病时间较晚。结论DV1-GZ01/03、DV1GZ02/03属于基因型Ⅳ型,与广东1995年流行株关系密切。乳鼠的神经毒性较弱可能与其基因变异有关。

Gene sequencing and analysis of the whole length of E gene from dengue virus type 1 isolated in Guangzhou area

Gene sequencing and analysis were undertaken for the two strains of dengue virus type 1 isolated from Guangzhou area(DV1-GZ01/03 and DV1-GZ02/03) in order to understand the possible origin of these strains of viruses and their biological characteristics,the envelope gene E of these two strains was amplified by RTPCR,the amplified fragments were cloned into vector pGEM-T and then sequenced. The C6/36 cells and sucking mice were infected with these strain of virus to perform the virulence tests,the homological analysis was undertaken by using the computer software and the data of reference and the epidemic strains of viruses to establish the phylogenetic trees.The experimental results showed that the whole length of nucleotides of DV1-GZ01/03 and DV1-GZ02/03 E gene was 1485 bp.These two stains were most close to dengue virus type 1 strain Austria/83,next to strain GD23/95.From analysis on the phylogenetic tree constructed,there were three distinct groups in 19 strains of dengue viruses from different area(I,V and IV genotypes),in which these two strains,strain Austria/83 and GD23/95 belonged to genotype IV.In addition,the cytopathogenic effect of these two strains and strain DV1-Hawaii was quite similar,but the virulence tested in sucking mice of these two strains appeared to be weaker than that of the strain DV1-Hawaii.It is concluded that the dengue virus type 1 strains DV1-GZ01/03 and DV1GZ02/03 belong to the genotype IV of dengue virus type 1,they may be originated from the strain GD23/95 and the low virulence of these strains of virus may be due to the development of gene mutation.