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Membrane permeability was reported to be modified by various animal virus during infection and the viral proteins responsible for this modification has been determined for poliovirus, influenza virus and HIV, etc. by an E. coli inducible system. In this study, the ability of the membrane permeability modification by Japanese encephalitis virus (JEV) nonstructural protein NS2b~NS3 was determined by the inducible system. Overexpression of NS2b plus various lengths of NS3 in E. coli causd membrane permeability change demonstrated by the entry of protein translation inhibitor) hygromycin B. The viral protein responsible for membrane modification was further mapped to NS2b since NS2b alone but not the N-terminus of NS3 retained this membrane modification ability. The region of NS2b required for this effect was localized to almost its full-length since the N-terminal 24-amino-acids deleted and the C-terminal 6-amino-acids deleted clones failed to demonstrate membrane modification ability. The NS2b's ability to modify membrane permeability was further proved by demonstrating the decrease of bacteria growth rate after protein induction, as well as the inpairment of eukaryotic cells' protein synthesis by a luciferase reporter system. In conclusion, JEV NS2b but not NS3 could modify membrane permeability.
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