The proteins of Murray Valley encephalitis virus

Proteins specified by Murray Valley encephalitis virus were labelled during virus growth in Vero and in PS cells, and separated by polyacrylamide gel electrophoresis. The purified virus particle contains three proteins (V-1, V-2 AND V-3) whereas the slow sedimenting haemagglutinin or virus sub-particle lacks the core protein V-2 but contains NV-2, a non-structural protein. Seven non-structural proteins in addition to V-2 and V-3 were identified in infected cells. Electrophoretic profiles by virus-specified proteins in both cell lines were almost identical after elimination by a double-label technique of the background of continuing host-cell protein synthesis. Glucosamine was incorporated into the envelope protein V-3 and NV-2. From 26 to 46h post-infection in Vero cells, the proportion and amounts of virus-specified proteins remained constant and they were non-equimolar; incorporation of labelled leucine into V-2 was much greater than incorporation into NV-2, whereas in cells infected with Kunjin (a related flavivirus) this ratio of incorporation was reversed. At 21 to 25h, the synthesis of V-2 was less prominent but there was an enhanced synthesis of NV-X. Apart from V-I, NV-I, NV-4 and NV-5, all proteins are larger than the corresponding Kunjin virus proteins and together represent about 400 x 10-3 daltons of polypeptide synthesis, which is close to the maximum coding content of the flavivirus genome.