Institute for Virus Research, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto, Japan.|Institute for Virus Research, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto, Japan.|Institute for Virus Research, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto, Japan.