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目的 测定对乳鼠不致病登革 2型病毒福建株 (DEN2 FJ11)全基因组序列 ,探讨其基因组结构与功能关系。方法 采用RT PCR和 5′、3′端RACE方法测定病毒基因组的全序列 ,并运用DNASTAR软件的Clustal法将该毒株的序列与其它 6株登革 2型病毒进行比较 ,分析其进化关系。结果 DEN2 FJ11株基因组全长 10 72 3个核苷酸 ,含有 1个单一的读码框架 ,编码 3391个氨基酸。 5′、3′端非编码区 (NCR)长度分别为 96和 45 4个核苷酸。DEN2 FJ11与同时分离的对乳鼠致病的FJ10株之间共有 32个核苷酸不同及 13个氨基酸的变化 ,其中 8个氨基酸是其极性或电荷的改变。 3′端非编码区 134位的单个核苷酸变化导致其二级结构改变。DEN2 FJ11与FJ10株的核苷酸和氨基酸的同源性分别为 99.7%和 99.6 %,这 2株病毒与印度尼西亚株亲缘关系最近 ,同为Ⅳ基因型。结论 DEN2 FJ11株基因组与FJ10株及其它登革 2型病毒株类似。位于病毒编码区的 8个氨基酸差异及 3′端非编码区 134位的核苷酸可能与病毒的乳鼠神经毒力有关。
Objective To determine the whole genome sequence of dengue 2 virus Fujian strain (DEN2 FJ11) which is not pathogenic to neonatal rats, and to explore the relationship between its genome structure and function. Methods RT-PCR and 5 ’, 3’ RACE were used to determine the full-length of the viral genome. The sequence of the virus was compared with 6 other dengue 2 viruses using Clustal method of DNASTAR software to analyze the evolutionary relationship. Results The genome of DEN2 FJ11 strain was 10 72 3 nucleotides in length and contained a single reading frame encoding 3391 amino acids. 5 ’, 3’ untranslated region (NCR) length of 96 and 454 nucleotides, respectively. There are 32 nucleotide variations and 13 amino acid changes between DEN2 FJ11 and the FJ10 strain isolated from offspring at the same time, of which 8 are amino acid changes in polarity or charge. A single nucleotide change at position 134 of the 3 ’non-coding region results in a change in its secondary structure. The nucleotide and amino acid homologies of DEN2 FJ11 and FJ10 strains were 99.7% and 99.6%, respectively. The two strains of viruses have the closest genetic relationship with the Indonesian strain and the same type Ⅳ genotype. Conclusion The genome of DEN2 FJ11 strain is similar to FJ10 strain and other dengue 2 strains. The 8-amino acid difference in the coding region of the virus and the nucleotide at the 134-position in the 3 ’non-coding region may be related to the virulence of the virus in neonatal gerbils.