Alteration in cyclic adenosine 3′:5′‐monophosphate binding proteins during the phenotypic change of mouse macrophages transformed by a temperature‐sensitive mutant ( tsA 640) of SV40

By using a photoaffinity ligand, cell extracts from transformed macrophages that were established by infection with temperature‐sensitive mutants ( tsA 640) of simian virus 40 (SV40) were examined for cyclic adenosine 3′:5′‐monophosphate (cAMP)‐binding proteins. At the nonpermissive temperature for SV40 large T antigen, 39.0°C, no significant cAMP‐binding proteins could be detected, such as primary mouse macrophages. At the permissive temperature of 33.0°C, cAMP‐binding proteins appeared later than SV40 T antigen expression and cellular DNA synthesis. The profile of cAMP‐binding proteins was similar to that of resting, but not proliferating, mouse clonal fibroblasts (BALB/c 3T3). These and previous results suggest that SV40 T antigen influences the expression of cAMP‐binding proteins in tsA 640‐transformed macrophages; the large/small T antigen converts the profile of cAMP‐binding proteins from macrophage to fibroblastic cells.