title: Glycoprotein E of the Japanese encephalitis virus forms virus-like particles and induces syncytia when expressed by a baculovirus.
abstract: The prM glycoprotein is thought to be a chaperone for the proper folding, membrane association and assembly of the envelope protein (E) of flaviviruses. The prM-E and E proteins of the Japanese encephalitis virus (JEV) were expressed in insect cells using both the baculovirus-expression system and the transient expression method. Protein expression was analysed by Western blotting and the cytopathic effect was observed by microscopy. In the baculovirus-expression system the E protein, with or without the prM protein, induced syncytial formation in Sf9 cells. Transient expression of prM-E also induced syncytia in Sf9 cells. Immunofluorescence revealed that in presence of prM, E proteins were endoplasmic reticulum-like in distribution, while in the absence of prM, E proteins were located on the cell surface. Sucrose gradient sedimentation and Western blot analysis indicated that the E protein expressed with or without the prM protein was secreted into the culture medium in particulate form. The formation of virus-like particles (VLPs) in the medium was confirmed by electron microscopy and immunoelectron microscopy. The results suggest that the E protein of JEV in the absence of prM, retained its fusion ability, by either cell surface expression or formation of VLPs. Moreover, based on the observation that co-expression of prM-E in Sf9 cells induced considerable syncytial formation, a novel, safe and simple antiviral screening approach is proposed for studying inhibitory antibodies, peptides or small molecules targeting the JEV E protein.
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
authors.forename: Ruikun
authors.initials: R
authors.lastname: Du
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
authors.forename: Manli
authors.initials: M
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
authors.forename: Hualin
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Deng
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D015153:Blotting, Western; D003588:Cytopathogenic Effect, Viral; D004664:Encephalitis Virus, Japanese / Q000235:genetics*; D015870:Gene Expression; D005822:Genetic Vectors; D015726:Giant Cells / Q000821:virology*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D008853:Microscopy; D055503:Protein Multimerization; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D061987:Sf9 Cells; D018411:Spodoptera; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000378:metabolism*; D022701:Virosomes / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins; D022701:Virosomes; C080628:glycoprotein E, Japanese encephalitis virus