FIG. 2.

C-Jun and c-Fos activate transcription from both JCV promoters. (A and B) Reporter constructs (5 μg) containing the JCV regulatory region in either the early (pBLCAT₃-Mad-1E) or late (pBLCAT₃-Mad-1L) orientation were transfected into U-87MG cells by the calcium phosphate method either alone or in combination with expression plasmids for c-Jun (RSV-c-Jun) and c-Fos (RSV-c-Fos). Expression plasmid concentrations used in transfection assays are shown. At 48 h posttransfection, promoter activity for each transfectant was determined with 100 μg of cell lysate and presented as chloramphenicol acetyltransferase activity relative to the basal expression of the promoter. The pBLCAT₃-Mad-1L and the pBLCAT₃-Mad-1E reporter constructs have been described (8). Expression plasmids for RSV-c-Jun and RSV-c-Fos were kindly provided by B. E. Sawaya (Temple University).