Detection of a precursor of bovine leukemia virus structural proteins in purified virions

Gel filtration chromatography of disrupted bovine leukemia virus (BLV) resulted in the isolation of the 25,000 dalton major virion internal protein and two previously uncharacterized virion proteins of molecular weight 65,000 and 12,000 respectively. The 65,000 dalton protein does not bind to concanavalin A and its antigenicity is ether-resistant. Therefore, this polypeptide is different from the previously described glycoprotein associated with BLV. Radiommunoprecipitation and competitive radioimmunoassays indicated that the 65,000 molecular weight polypeptide shares antigenic determinants with the 25,000, 15,000, and 12,000 dalton BLV proteins, respectively. Thus, the 65,000 dalton polypeptide may represent the precursor of these three smaller virion proteins.