Precursor polypeptides of caprine arthritis-encephalitis lentivirus structural proteins

1 Department of Veterinary Microbiology and Pathology and 2 U.S. Department of Agriculture, Animal Disease Research Unit, Washington State University, Pullman, Washington 99164, U.S.A. The synthesis of caprine arthritis-encephalitis virus structural proteins was analysed in infected cells labelled with [ 35 S]methionine and [ 3 H]glucosamine and by translation of virion RNA in vitro . Viral polypeptides were isolated from infected cell lysates or from in vitro translation products by immunoprecipitation with specific antisera and resolved by SDS-PAGE. Results indicated that the gag gene-encoded p28, p19 and p16 virion core proteins were formed by cleavage processing of a 55K M r precursor with several intermediate polypeptides. The gp135 virion surface glycoprotein, encoded by the env gene, was formed by post-translational modification of a glycosylated precursor of 150K apparent M r . This precursor was formed by glycosylation of a 90K primary env gene product. Keywords: CAEV, lentivirus, structural proteins Received 15 September 1987; accepted 18 November 1987.