A Comparison of the Intracellular Precursor Polyproteins of Simian Sarcoma-associated Virus [SiSV(SiAV)] and Three Human Virus Isolates: HL23V, HEL12V and A1476V

Abstract

SUMMARYThe intracellular precursor polyproteins of simian sarcoma-simian-associated virus [SiSV(SiAV)] were compared to the intracellular proteins of the human retrovirus isolates, HL23V, HEL12V and A1476V, by radioimmunoprecipitation followed by SDS-polyacrylamide gel electrophoresis and tryptic peptide analysis. Cells infected with SiSV(SiAV) were characterized by polyproteins Pr200 gas-p°), gPr80 env, Pr80 gag, Pr60 gag and Pr40 gag. Identical intracellular precursor polyprotein profiles were obtained from cells infected with HL23V, HEL12V and A1476V. Tryptic digest mapping of peptides containing [3H]leucine showed the structural composition of Pr60 gag to be the virus core proteins, p28, p15/p12 and pl0. The SiSV(SiAV) envelope precursor, gPr80 env, contained the structural determinants of mature viral gp70 and a non-glycosylated protein termed p15E. The homology of the human isolate viruses, HL23V, HEL12V and A1476V, to the SiSV(SiAV)/ GaLV (gibbon ape leukaemia virus) family of viruses was confirmed by mapping studies. Both gPr80 env and Pr60 gag of SiAV were identical by tryptic peptide mapping to the respective proteins from the three human retrovirus isolates examined. The potential significance of these results to considerations of the origins of SiAV and the SiAV-like human isolates is discussed.