Identification and molecular characterization of a new nonsegmented double-stranded RNA virus isolated from Culex mosquitoes in Japan.
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.
Isawa
Haruhiko
H
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. hisawa@nih.go.jp
Kuwata
Ryusei
R
Hoshino
Keita
K
Tsuda
Yoshio
Y
Sakai
Kouji
K
Watanabe
Shumpei
S
Nishimura
Miho
M
Satho
Tomomitsu
T
Kataoka
Michiyo
M
Nagata
Noriyo
N
Hasegawa
Hideki
H
Bando
Hisanori
H
Yano
Kazuhiko
K
Sasaki
Toshinori
T
Kobayashi
Mutsuo
M
Mizutani
Tetsuya
T
Sawabe
Kyoko
K
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
D012330:RNA, Double-Stranded; D012367:RNA, Viral; D014764:Viral Proteins