Nucleotide and deduced amino acid sequence of the structural protein genes of Japanese encephalitis viruses from different geographical locations

Abstract

Strain variation among Japanese encephalitis (JE) virusisolates has been previously demonstrated by many workers using different methods. We report the nucleotide sequence of the 5' non-coding region and the nucleotide and deduced amino acid sequences of structural protein genes for eight wild-type JE virus strain isolated from different Asian countries (Vietnam, Nepal, Indonesia, Thailand, India, Japan and China). We compare these with five other published wild-type JE virus strains isolated from Japan and the mainland of China. No strain variation could be related to geographical location on the basis of the wild-type JE virus strains studied. The viruses differed from each other by between 21 (0.9 %) and 111 (4-6%) nucleotides and by between 3 (0.4%) and 31 (4.2%) amino acids over the 2434 nucleotides examined. The amino acid divergence of the envelope (E) protein gene of the viruses was 4.2 % or less among the 13 strains compared. Thus there is little genetic divergence in the strains studied. However, four variable E protein amino acids (E-51, E-209, E-244 and E-366) were identified. Residue positions E-51, E-244 and E-366 are found in peptides with functional T helper cell epitopes in two other flaviviruses. Therefore, these amino acids may be important in defining the various immunotypes of JE virus identified by antibody reactivity patterns.

Age-Related Susceptibility to Japanese Encephalitis Virus in Domestic Ducklings and Chicks

“…The second strain of virus (JE-P3) was isolated from mosquitoes in China in 1949 and had been passaged extensively in suckling mice and cultured cells. 22 Molecular sequencing of the pre-membrane region of both viruses confirmed that the viruses represented genotypes I (JE-VN) and III (JE-P3) respectively.…”

Phylogenetic analysis of Japanese encephalitis virus: envelope gene based analysis reveals a fifth genotype, geographic clustering, and multiple introductions of the virus into the Indian subcontinent.

“…The functional significance of this high level of nucleotide variation within this 240 nt prM region has therefore yet to be established. 17 Indeed, earlier reports have shown that the use of short stretches of nucleotides or amino acids in phylogenetic analysis 35,36 results in incorrect tree topologies, suggesting that the 240 nt prM region is not the ideal candidate for studying the molecular evolution of JEV.…”

“…9 Immunotyping and oligotyping data suggest that strain variation among JE viruses is not related to geographic location. 16,[37][38][39] Comparison of nucleotide and amino acid sequence of envelope genes of thirteen JEV strains 17 showed no clustering based on geographical location. However, Chen and coworkers 9 used forty-six prM sequences to show that JEV isolates from the same geographic region and time period are similar.…”

“…The literature on this topic is conflicting. 9,17 Therefore, an exhaustive tree building exercise was undertaken with all 107 unique envelope sequences available in the database of JEV strains from geographically diverse regions of Asia. This revealed the hitherto unrecognized fifth genotype of JEV.…”

Genotypes of Japanese Encephalitis Virus Isolated in Three States in Malaysia

“…@7 Compar ative study of the nucleotide and deduced amino acid se quences of the core (C), pre-membranc (prc-M), membrane (M), and envelope (E) coding regions between five JEV strains, Nakayama-RFVL, Beijing-l, Kamiyama, Muar, and 691004, suggested that the Muar strain was the most struc turally different from the other four strains, in agreement with the results using a hcmagglutination inhibition test with JEV-spccics-specific monoclonal antibodies.4 Primer-exten sion sequencing of the gcnomic RNA template of JEV has provided new information on the geographic distribution, or igin, and evolution of this virus.5 6 Two hundred forty nu cleotides from the pre-M gene region of JEV isolates were analyzed, and the results showed the existence of four dis tinct JEV genotypes in Asia and suggested that genetic van ations occurred among strains from different time periods in the same region. In addition, it has been recently reported that the nucleotide sequence of the pre-M protein region was the most variable among the structural protein genes C, pre-M, M, and E. 7 The purpose of this study was to analyze 12 JEV strains isolated in three regions of Malaysia from 1993 to 1994, and to explore their genetic relationships.…”