Isolation and characterisation of the rabies virus N°-P complex produced in insect cells

When the nucleoprotein (N) of nonsegmented negative-strand RNA viruses is expressed in insect cells, it binds to cellular RNA and forms N-RNA complexes just like viral nucleocapsids. However, in virus-infected cells, N is prevented from binding to cellular RNA because a soluble complex is formed between IN and the viral phosphoprotein (P), the Ndegrees-P complex. N is only released from this complex for binding to newly made viral or complementary RNA. We coexpressed rabies virus IN and P proteins in insect cells and purified the Ndegrees-P complex. Characterisation by gel filtration, polyacrylamide gel electrophoresis, analytical ultra centrifugation, native mass spectroscopy, and electron microscopy showed that the complex consists of one N protein plus two P proteins, i.e., an Ndegrees-P-2 complex. (C) 2003 Elsevier Science (USA).