Identification and characterization of the short variable region of the Japanese encephalitis virus 3′ NTR

• Published in: Virus genes Vol. 44; no. 2; pp. 191 - 197
• Main Authors: Kato, Fumihiro, Kotaki, Akira, Yamaguchi, Yukie, Shiba, Hajime, Hosono, Kuniaki, Harada, Seiya, Saijo, Masayuki, Kurane, Ichiro, Takasaki, Tomohiko, Tajima, Shigeru
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-04-2012; Springer Nature B.V
• Subjects: 3' Untranslated Regions; Animals; Biomedical and Life Sciences; Biomedicine; Cell Line; Culicidae; Encephalitis Virus, Japanese - genetics; Encephalitis Virus, Japanese - growth & development; Encephalitis Virus, Japanese - pathogenicity; Female; Genetic Variation; Japanese encephalitis virus; Medical Microbiology; Mice; Molecular Sequence Data; Mutagenesis, Insertional; Plant Sciences; Recombination, Genetic; RNA, Viral - genetics; Sequence Analysis, DNA; Sequence Deletion; Virology; Virulence; Virus Replication; Infectious clone; Japanese encephalitis virus; 3′ NTR; Variable region
• ISSN: 0920-8569; 1572-994X
• DOI: 10.1007/s11262-011-0685-6

Since the 1980s, the Japanese encephalitis virus (JEV) variants with slightly short variable regions (VR) of the 3′ non-translated region (NTR) have been found; however, the implications of these short VR remain unclear. We recently identified two novel types of short VR (5 and 9 nt shorter than that of major group of genotype I JEV strains) of genotype I JEV isolates. To elucidate the impact of these short VR on the replication and virulence of JEV, we generated five recombinant JEV viruses: M41-d5 and M41-d9 have deletions in the VR that correspond to those observed in some recent JEV isolates, M41-d5d9 has both the 5- and 9-nt deletions in the VR, M41-d27 has a large deletion that encompasses both the 5- and 9-nt deletion regions, and M41-a13 has a 13-nt sequence insertion of the genotype III JEV strain Beijing-1 into the parent genotype I JEV strain Mie/41/2002 genome. The recombinant viruses and the parent virus, except for the M41-d27 mutant, showed similar growth properties in mammalian and mosquito cell lines. Mouse challenge experiments indicated that no significant differences among the recombinant viruses M41-d5d9, M41-d27, M41-a13, and the parent virus. Our results suggest that the short VR in JEV 3′ NTR do not affect its growth in vitro or its pathogenicity in mice.