Activation of myogenic program in MadMyc chimera transiently transfected RD cells. A. Luciferase assay of lysate from RD cells co-transfected with the empty vector (CMV) or MadMyc- or c-Myc-expressing vectors and the plasmid carrying myogenin promoter (pMyo84-luc). The histogram shows the fold induction of myogenin promoter (pMyo84-luc) of MadMyc- or c-Myc- versus CMV-transfected RD cells arbitrarily set at 1. Data show mean values ± s.e.m. of triplicates of two experiments. B. Immunoblotting of parallel culture as in (A) with antibodies for indicated proteins. C. Immunofluorescence with antibody directed to sarcomeric myosin (MHC) of RD cells stably transfected with MadMyc chimera, c-Myc and CMV after 4 days of plating (middle panels). Cell nuclei were stained with DAPI (upper panels). Photomicrographs by contrast phase (lower panels) of other fields. Similar results were obtained in two experiments.