title: [Recent research on the JC virus].
abstract: JC virus (JCV) is a causative agent of progressive multifocal leukoencephalopathy and belongs to Polyomavirus. In this article we describe our recent research relating to this virus. First, JCV's major capsid protein VP1 possesses a nuclear localization signal (NLS) and has the ability to construct a virus-like particle (VLP). We have investigated the mechanism of nuclear entry of JCV using VLP, and clarified the role of NLS. In vitro transport assay revealed that wild type VLP (wtVLP), but not deltaNLSVLP, entered the nuclei of cells. The nuclear transport of wtVLP was dependent on the addition of importins alpha and beta and was prevented by antibodies to nuclear pore complex (NPC). These results suggested that JCV VLP binds to cellular importins via the NLS of VP1 and is transported into the nucleus through the NPC. Second, a yeast two-hybrid screen of a human brain cDNA library demonstrated that the fasciculation and elongation protein zeta 1 (FEZ1) and the heterochromatin protein lalpha (HPla) are proteins that interacted with JCV agnoprotein (Agno). In vitro binding assay showed that Agno interacts directly with FEZ1 and HPlalpha. We have also shown that Agno induces the dissociation of FEZ1 from microtubules and dissociates the interaction between HPlalpha and lamin B receptor. We have demonstrated that interaction between Agno and these host proteins inhibited nuclear egress of JCV. Third, in order to inhibit JCV infection in infected cells, we synthesized siRNA which is specific for JCV Agno. Immunoblotting and immunocytochemical analysis demonstrated that expression levels of agnoprotein and VP1 were significantly inhibited by specific siRNA. In addition, levels of viral mRNAs and viral production were decreased in the cells transfected with Agno siRNA. Furthermore, viral production of cell treated with Agno siRNA was significantly inhibited. These results indicate that post-infection treatment with siRNAs, that targets JCV Agno suppresses virus production in JCV infected cells. Thus, siRNA directed against JCV encoding genes may provide a useful tool for suppression of JCV infection.
authors.affiliation: Department of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Nishi 9, Kita 18, Kita-ku, Sapporo 060-0818, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sawa
authors.forename: Tadaki
authors.initials: T
authors.lastname: Suzuki
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Orba
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sunden
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagashima
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000974:Antibodies, Antinuclear; D036022:Capsid Proteins / Q000502:physiology; D002467:Cell Nucleus / Q000821:virology; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D006801:Humans; D007577:JC Virus; D028884:Karyopherins / Q000502:physiology; D007968:Leukoencephalopathy, Progressive Multifocal / Q000188:drug therapy / Q000821:virology; D009419:Nerve Tissue Proteins; D019913:Nuclear Localization Signals / Q000502:physiology; D022022:Nuclear Pore / Q000276:immunology; D034741:RNA, Small Interfering / Q000627:therapeutic use; D012367:RNA, Viral / Q000627:therapeutic use; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*; D054334:Viral Regulatory and Accessory Proteins; D000086082:Viroporin Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000974:Antibodies, Antinuclear; D036022:Capsid Proteins; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D028884:Karyopherins; D009419:Nerve Tissue Proteins; D019913:Nuclear Localization Signals; D034741:RNA, Small Interfering; D012367:RNA, Viral; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C528597:FEZ1 protein, human; C118711:LZTS1 protein, human; C062481:VP1 protein, polyomavirus; C042559:agnoprotein, polyomavirus; D000086082:Viroporin Proteins