Characterization of a serine-to-asparagine substitution at position 123 in the Japanese encephalitis virus E protein.

Yukie Yamaguchi, Yoko Nukui, Akira Kotaki, Kyoko Sawabe, Masayuki Saijo, Haruo Watanabe, Ichiro Kurane, Tomohiko Takasaki, Shigeru Tajima

Department of Virology 1, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, Japan.

The Journal of general virology 2013 Jan

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Amino acid position 123 in the E protein of Japanese encephalitis virus (JEV) determines viral growth properties and pathogenicity. The majority of JEV strains have a serine residue at this position (E(123S)); however, JEV with an asparagine residue (E(123N)) has also been isolated. To compare the growth properties and pathogenicity of E(123S) and E(123N) JEV, we produced recombinant JEV with a serine-to-asparagine substitution at position 123 (rJEV-Mie41-E(S123N)) in the E(123S)-type strain Mie/41/2002 background. The growth rate of rJEV-Mie41-E(S123N) was similar to that of Mie/41/2002 in mammalian and mosquito cell lines. Mouse challenge experiments showed that there was only a slight difference in neuroinvasiveness between the parent strain (Mie/41/2002) and rJEV-Mie41-E(S123N). Thus, our results indicate that the Ser-to-Asn substitution in the JEV E protein has weak impact on viral growth properties in vitro or on pathogenicity in vivo.

Citation

Yukie Yamaguchi, Yoko Nukui, Akira Kotaki, Kyoko Sawabe, Masayuki Saijo, Haruo Watanabe, Ichiro Kurane, Tomohiko Takasaki, Shigeru Tajima. Characterization of a serine-to-asparagine substitution at position 123 in the Japanese encephalitis virus E protein. The Journal of general virology. 2013 Jan;94(Pt 1):90-6