Fig. 5. Transcription from the VDR reporter gene induced by c-MYB. In A, COS 7 cells were transiently transfected with 0.2 µg of VDR reporter gene construct and with increasing amounts of c-MYB expression construct (0.3, 0.5, and 0.8 µg). Luciferase activities were normalized against the activities of the control vector pRL-null. B, coactivation of the induction of the VDR promoter by c-MYB and CBP. COS 7 cells were transiently transfected with 0.2 µg of VDR reporter gene construct and c-MYB (0.3 µg), CBP (0.3 µg), or the combination of c-MYB and CBP expression vectors. Luciferase activity was assayed at 48 h after transfection. Luciferase activities of the VDR reporter construct were normalized against the activities of the pGL3Basic vector alone, because CBP has an inducing effect on the control itself. C, additive induction of the transcription from the VDR promoter by c-MYB and ZEB. COS 7 cells were transiently transfected with 0.2 µg of VDR reporter gene construct and c-MYB (0.3 µg), ZEB (0.3 µg), or the combination of c-MYB and ZEB expression vectors. Luciferase activity was assayed at 48 h after transfection. Luciferase activities were normalized against the activities of the control vector pRL-null. The average of three independent transfections and SDs are shown. Experiments with very small SDs do not show observable error bars.