Dominant inhibitory effect of expression of M-Ras S27N on activation of c-fos promoter by activated Src Y527F. 293-cells were transfected as described in the legend to Fig 8 with 0.25 μg of the c-fos luciferase reporter plasmid and 0.25 μg of a Src Y527F plasmid and the indicated amount in micrograms of the indicated plasmids. Shown are relative luciferase units expressed as the mean ± SD of 3 independent experiments.