Strain specificity of changes in adenylate cyclase activity in cells transformed by avian sarcoma viruses

Chick embryo fibroblasts transformed by avian sarcoma viruses, B77, the Prague strain of Rous sarcoma virus (PR-RSV), and the Schmidt-Ruppin strain of RSV (SR-RSV) had lower activity of adenylate cyclase, but the same activity of cyclic AMP phosphodiesterase as control cells. The cells infected with their temperature-sensitive mutants in the transforming capacity also had reduced cyclase activity when grown at 36°, but normal activity when grown at 41°, showing a close correlation between viral transformation and cellular adenylate cyclase activity. The characteristics, Km value for ATP, Mg 2+ ion dependency, and sensitivity to NaF, of the adenylate cyclase activity reduced by viral transformation varied with the viral strain. It was concluded that the changes of the enzyme activity on transformation were specific to the virus strain used and were not related to the subgroup of virus.