In vitro synthesis of infectious DNA copies of the Rous sarcoma virus genome

Detergent-disrupted virions of Rous sarcoma virus can synthesize in vitro an infectious viral DNA. Infectivity of the DNA was determined in transfection assays at the endpoint dilution. It was found that the specific infectivity of the crude endogenous reaction product was 34 infectious units/microgram. The endogenous reaction yielded up to 8.5 x 10(-7) infectious units per biologically active input virion, i.e., nearly 0.1 -1 infectious molecules. The possible structure of these molecules is discussed.