广东省流行的3株登革热2型病毒基因组全序列测定及分析

目的测定广东省3株登革热2型病毒的全序列,探讨其来源及基因型。方法运用RT PCR法扩增来自广东省的登革热2型GD09/93、GD05/98和GD19/2001病毒株的全序列,采用遗传距离法构建进化树。结果3株登革热2型病毒的全基因组长度均为10 723 nt,5′及3′端各有一非编码区,结构基因和非结构基因位于基因组97~10 269 nt之间,共编码3391个氨基酸,读码结构完全相同。GD05/98与GD09/93、GD05/98与GD19/2001、GD09/93与GD19/2001之间的碱基序列同源性分别为93.3%、92.4%和97.6%,氨基酸序列同源性分别为96.7%、96.5%和98.5%。结论3株登革热2型病毒均对乳鼠致病,与对乳鼠不致病的参考株（DEN2-04株）比较共有18个氨基酸位点的差异引起极性或电荷变化,PrM-134、NS2A-153、NS4B-102所带电荷的变化对抗原性影响较大。GD05/98株与泰国分离株同为Ⅱ基因型,GD09/93和GD19/2001株与印度尼西亚、澳大利亚、台湾株分在Ⅳ基因型;表明我国登革热2型病毒有不同的基因型,而不同时期也存在同一种基因型传播。

Determination and analysis of complete genomic sequences of three Dengue 2 virus strains isolated in Guangdong province, China

Objective To dete ine the complete genomic seqnenees of 3 Dengue 2 virus （DEN-2） strains isolated in Guangdong province, China and to investigate their genotypes and sources. Methods The complete genomic sequences of 3 DEN-2 strains （GD09/93, GD05/98, and GD19/2001） from Guangdong province were established by RT-PCR amplification. The phylogenetic tree of DEN-2 was constructed by Kimura method. Results The complete genomic sequences of 3 DEN-2 strains were 10 723 nucleotides （nt） in length and contained a single long open reading frame （ORF） of 10 173 nucleotides （97-10 269 nt）, encoding 3391 amino acids. The ORF encoded structural and non-structural proteins, flanked by 5＇ and 3＇ non-coding regions. Comparing GD05/98 with GD09/93, GD05/98 with GD19/2001, and GD09/93 with GD19/2001, the nucleotide sequence homologies were 93.3%, 92.4%, and 97.6%, respectively, and the deduced amino acid sequence homologies were 96.7%, 96.5%, and 98.5%, respectively. Conclusion The DEN-2 strains are pathogenic in suckling mice. Compared with DEN-2-04 strain （nonpathogenic in suckling mice）, there are 18 amino acid substitutions that confer changes in charge or polarity. The charge changes at PrM-134, NS2A-153, and NS4B-102 have a relatively strong impact on the antigenicity. GD05/98 strain falls within the group 1] comprising Thailand strains, while GD09/93 and GD19/2001 strains fall within the group 1V comprising strains from Indonesia, Australian and Taiwan. There are different DEN genotypes in China, and one genotype of DEN-2 may be transmitted in different periods.