title: Identification and molecular characterization of a new nonsegmented double-stranded RNA virus isolated from Culex mosquitoes in Japan.
abstract: Two infectious agents were isolated from Culex species mosquitoes in Japan and were identified as distinct strains of a new RNA virus by a method for sequence-independent amplification of viral nucleic acids. The virus designated Omono River virus (OMRV) replicated in mosquito cells in which it produced a severe cytopathic effect. Icosahedral virus particles of approximately 40 nm in diameter were detected in the cytoplasm of infected cells. The OMRV genome was observed to consist of a nonsegmented, 7.6-kb double-stranded RNA (dsRNA) and contain two overlapping open reading frames (ORFs), namely ORF1 and ORF2. ORF1 was found to encode a putative dsRNA-binding protein, a major capsid protein, and other putative proteins, which might be generated by co- and/or post-translational processing of the ORF1 polyprotein precursor, and ORF2 was found to encode a putative RNA-dependent RNA polymerase (RdRp), which could be translated as a fusion with the ORF1 product by a -1 ribosomal frameshift. Phylogenetic analysis based on RdRp revealed that OMRV is closely related to penaeid shrimp infectious myonecrosis virus and Drosophila totivirus, which are tentatively assigned to the family Totiviridae. These results indicated that OMRV is a new member of the family of nonsegmented dsRNA viruses infecting arthropod hosts, but not fungal or protozoan hosts.
authors.affiliation: Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. hisawa@nih.go.jp
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Isawa
authors.forename: Ryusei
authors.initials: R
authors.lastname: Kuwata
authors.forename: Keita
authors.initials: K
authors.lastname: Hoshino
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tsuda
authors.forename: Kouji
authors.initials: K
authors.lastname: Sakai
authors.forename: Shumpei
authors.initials: S
authors.lastname: Watanabe
authors.forename: Miho
authors.initials: M
authors.lastname: Nishimura
authors.forename: Tomomitsu
authors.initials: T
authors.lastname: Satho
authors.forename: Michiyo
authors.initials: M
authors.lastname: Kataoka
authors.forename: Noriyo
authors.initials: N
authors.lastname: Nagata
authors.forename: Hideki
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Hisanori
authors.initials: H
authors.lastname: Bando
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yano
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sasaki
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizutani
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sawabe
mesh_terms: D000818:Animals; D002460:Cell Line; D016000:Cluster Analysis; D003465:Culex / Q000821:virology*; D003588:Cytopathogenic Effect, Viral; D003593:Cytoplasm / Q000821:virology; D007564:Japan; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D012330:RNA, Double-Stranded / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D019196:Totiviridae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification* / Q000648:ultrastructure; D014764:Viral Proteins / Q000235:genetics; D014771:Virion / Q000648:ultrastructure
chemical_list: D012330:RNA, Double-Stranded; D012367:RNA, Viral; D014764:Viral Proteins