In vitro translation of a 180,000-dalton rous sarcoma virus precursor polypeptide containing both the DNA polymerase and the group-specific antigens

Translation of 34S RNA from the Prague C strain of Rous sarcoma virus RSV (Pr-C) in a Kreb's ascites cell-free protein synthesizing system leads to synthesis of three detectable viral precursor polypeptides with electrophoretic mobilities corresponding to molecular weights of about 180,000, 70,000, and 65,000 daltons. The 180,000-dalton protein is precipitated by antiserum directed against purified 13,77 avian sarcoma virus reverse transcriptase as well as by serum against AMV group-specific (gs) antigens, but is not precipitated by serum directed against RSV (Pr-C) gp85. The 70,000- and 65,000-dalton proteins are precipitated by antiserum directed against gs antigens but not by antisera directed against polymerase, MuLV (Friend) p30, or RSV (Pr-C) gp85. Competition experiments with purified polymerase and gs antigens indicate that the 180,000-dalton protein has separate determinants for the gs antigens and polymerase.