Figure 8.

(Left) The effect of signal transduction (ant)agonists on transactivation of the γD promoter by c-Maf in CHO cells. CHO cells were transfected with the –73/+10 γD–luciferase construct and an expression construct for c-Maf as described in Materials and Methods. Signal transduction (ant)agonists were added as indicated at the following concentrations: forskolin, 100 µM; PD98059, 20 µM; SB203580, 10 µM; TPA, 1 µg/ml. The relative activation was calculated from the increase in activity during the time that the signal transduction (ant)agonists were present, where the increase in activity in the absence of (ant)agonists but in the presence of c-Maf was set at 1. As a control, activation of a CRE–luciferase reporter gene by forskolin was also determined. To avoid problems with the scale, the activity of the CRE reporter gene in the presence of forskolin was set at 1. (Right) The behaviour of c-Maf mutants. CHO cells were co-transfected with a –73/+10 γD–luciferase construct and an expression construct for c-Maf or mutants thereof, as indicated. The activity of the mutants is expressed relative to that of wild-type c-Maf, which was set at 1.