The structure of the Rous sarcoma virus glycoprotein complex: in vitro phenotypic mixing of rous sarcoma virus

Gp 85 the major envelope glycoprotein of Rous sarcoma virus can be released from intact by virus treatment with 2-mercaptoethanol. Attempts were made to reassociate released gp 85 to 2-mercaptoethanol treated virus. In order to study the biological activity and to analyse the reaction product with biochemical methods gp 85 from a subgroup different from the recipient virus was used. Successful in vitro phenotypic mixing could be shown. The biochemical analysis, however, revealed that no reassociation of gp 85 and gp 35 could be obtained. The biological activity was due to a strong association of whole gp 85-gp 35 molecules derived from the gp 85 preparation to the recipient virus. These molecules were present as a minor contamination in the gp 85 preparation.