title: A variant of western equine encephalitis virus with nonglycosylated E3 protein.
abstract: A variant clone (At/A125) of western equine encephalitis virus was isolated from a line of mosquito cells persistently infected with a temperature-sensitive parent strain, A125. Variant-infected cells produced an altered form of PE2 protein which migrated with a higher electrophoretic mobility than wild type or A125 PE2. The altered PE2, like PE2 of wild type, was precipitated by anti-envelope proteins serum but not by anti-E1 serum. In pulse-chase experiments the altered PE2 protein was shown to yield E2 of normal electrophoretic mobility in SDS-polyacrylamide gel electrophoresis. The unglycosylated form of the altered PE2 synthesized in the presence of tunicamycin migrated at the same position as the unglycosylated PE2 obtained from tunicamycin-treated, parent strain-infected cells. This suggested that migration difference might be ascribable to incomplete glycosylation of PE2, possibly of its E3 component. E3 is released into culture fluid of wild-type-infected cells as an approximately 11-kd glycoprotein, while variant-infected culture fluid yielded a smaller, apparently virus-specific protein. The protein could not be labeled with [3H]mannose, suggesting that the polypeptide moiety of E3 in the variant infected cells failed to be glycosylated. The parent strain, A125, and a revertant of the variant, At/A125/rev, did not synthesize such altered PE2 and E3 proteins. The growth of At/A125 in mosquito cells was similar to that of parent or wild type but depressed in vertebrate cells.
mesh_terms: D000330:Aedes; D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D004666:Encephalitis Virus, Venezuelan Equine / Q000254:growth & development; D004667:Encephalitis Virus, Western Equine / Q000235:genetics / Q000378:metabolism*; D014644:Genetic Variation; D014415:Tunicamycin / Q000494:pharmacology; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D014759:Viral Envelope Proteins; D014764:Viral Proteins; D014415:Tunicamycin