Figure 2

GR inhibits p53 and p73 transcriptional activity. A, Saos-2 cells were transfected with DNAs encoding p53 (50 ng), the indicated p53/p73-responsive reporter DNA (pG13-luc, p21-luc, or MDM2-luc, 100 ng each), and GR (100, 250, 500 ng for pG13-luc; 500 ng for p21-luc and MDM2-luc). 24 hrs after transfection, cells were untreated or treated with dexamethasone (100 nM) for an additional 20 hrs. Luciferase activity in transfected cell lysates was determined. The fold change in pG13-luc activity is plotted (+/- standard error of the mean, s.e.m.) from multiple experiments compared to the activity of pG13-luc alone, whose value is considered 1.0. Relative luciferase activity (RLU) is plotted (+/- s.e.m.) for MDM2-luc and p21 luc. Representative immunoblots for each experiment are shown. B, Same as in A above, but with transfection of p73β DNA (50 ng).