广东流行的三株登革1型病毒包膜蛋白基因的序列测定与分析

Analysis of the E gene sequences of three dengue virus type 1 isolates in Guangdong province

目的通过对广东省不同地区、不同流行期间分离的三株登革1型病毒(DV1)的结构蛋白E基因进行序列测定及分析,了解各流行株之间的遗传差异,追踪其可能的传染来源.方法应用RT-PCR技术扩增病毒的结构蛋白E基因,克隆到PMD18-T载体,转化JM109宿主菌,挑取阳性克隆进行鉴定及序列测定,应用计算机软件与国内外参考及流行株进行同源性分析,并绘制基因系统发生树.结果3株DV1病毒E基因序列长度均为1 485bp,编码495个氨基酸,核苷酸序列同源性在91%～98%之间,推测的氨基酸序列同源性在94%～99%之间.GD23/95与A88核苷酸(氨基酸)同源性为95%(98%),与其他株的同源性相对较低,2株属同一基因型;GD14/97和GD05/99与Cambodia共享序列非常接近,3株同属另一基因型.结论广东省1997、1999和1995年流行的登革热可能来自境外不同的疫源地.

Objective To trace the infection sources of three dengue virus type 1 isolates found in Guangdong province, namely GD05/99, GD14/97 and GD23/95. Methods According to the genomes of dengue virus type 1 S275 strain, a pair of primers was designed for amplification of the structural protein E gene of the isolated dengue virus type 1 strains by reverse transcriptase-PCR. The amplified gene fragment was then cloned into pMD18-T vector and sequenced. Results GD14/97 and GD05/99 shared a high nucleotide homology with Cambodia (98% and 99% respectively) and may belong to the same genotype. GD23/95 had a 95% nucleotide homology with A88, higher than that with other strains. GD23\95 and A88 may belong to another genotype. Conclusion The dengue fever outbreak in Guangdong during 1999, 1997, and 1995 may originate from the viruses from different countries.