Precursor Polypeptides of Caprine Arthritis-Encephalitis Lentivirus Structural Proteins

The synthesis of caprine arthritis-encephalitis virus structural proteins was analysed in infected cells labelled with [35S]methionine and [3H]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.