Cloning and Sequence Analysis of the Full-Length Genome of Japanese encephalitis virus Strain SXBJ07 Isolated from Swine

A virus strain, showing cytopathic effect in BHK-21 cell, was isolated from swine brains in Shaanxi Province, China, in 2007. The isolate was confirmed as Japanese encephalitis virus (JEV) by immunofluorescence assay (IFA) and reverse transcription polymerase chain reaction (RT-PCR), and named SXBJ07. The complete nucleotide and deduced amino acid sequences of the JEV strain SXBJ07 were determined. Its single open reading frame has a total of 3 432 amino acid residues. An extensive E gene based phylogenetic analysis was performed, the result showed that SXBJ07 strain belongs to genotype I. Comparison of the SXBJ07 genomic sequence with those of the 24 fully sequenced JEV strains in published databases showed nucleotide homology ranging from 99.0 to 83.7%; amino acid homology ranged from 99.8 to 94.8%. Compared SXBJ07 with SA14-14-2 strain, the current live vaccine strain in China, the homology of amino acid in envelope gene was 97.0%; and there were amino acid substitutions in 13 sites of the active domains of E protein (E1-E411).