中文摘要：

目的分析中国首次分离的基因I型流行性乙型脑炎病毒（JEV）全基因组的基因组特征。方法设计JEV全基因组扩增引物，RT—PCR扩增片断，PCR产物直接测序，拼接后获得全基因组序列。采用生物学软件进行同源性和系统进化分析。结果1977和1982年分离自云南蚊虫的M28和BN82215病毒株基因组全长分别为10969bp和10970bp，5’非编码区均含有96个核苷酸，3’非编码区含有573和574个核苷酸。它们的开放阅读框（ORF）都从97到10396位，共10299个核苷酸，编码3433个氯基酸。M28和BN82215株与来自GenBank的5个基因型JEV株的全基因组核苷酸和氨基酸同源性分别为78．4％～96．3％和91．4％～99．6％，与近几年国内外基因I型流行株的同源性最高，进化关系最接近，都属于基因I型。这两株病毒与JEV疫苗株SAl4142相比，有56个氨基酸差异，其中E基因有11个氨基酸差异，但都不属抗原关键位点。结论本研究阐明了中国首次分离的基因I型JEV的全基因组分子特征，决定病毒抗原和毒力的E蛋白关键位点无明显变化。证实20世纪70和80年代云南省就有基因I型JEV流行。

英文摘要：

Two strains of Japanese encephalitis virus （JEV）, M28 and BN82155, isolated from Yunnan Province respec tively in 1977 and 1982, are the first isolates of genotype I JEV in China. In this study, full-length genomes of them, one con taining an ssRNA molecule of 10 969 nt and the other 10 970 nt in length, were characterized. Both of them have a single 10 299-nucleotide open reading frames （ORF）, encoding 3 433 anaino acids. Compared with other representative strains of five genotypes retrieved from GenBank, M28 and BN82215 showed 78.4~~-96.3~ nucIeotide homology and 91.4~-99.6~ amino acid homology respectively, displaying close relationship with Genotype I JEV isolates circulating both in China and aboard in recent years. A total of 56 deduced amino acid residuals were observed differing from SA14-14-2 JE vaccine strain, with 11 amino acid mutations in the E gene. However, none of them was associated with known critical antigenic and virulent sites. In summary, characterization of first two genotype I JEV isolates from China demonstrated the prevalence of this genotype in Yunnan Province several decades ago.