Evaluation of PRB and Gata2 contribution to the progesterone regulation of Ednra expression. A, The Gata2 siRNA efficiently reduced Gata2 protein levels in 293E cells at 200μM concentration, including in cells transfected with PRB and treated with progesterone for 24 hours. The scrambled sequence (Scr.) control siRNA had no effect on Gata2 protein levels and did not prevent the increase of Gata2 protein in PRB-transfected cells treated with progesterone. B, The Gata2 siRNA decreased the luciferase activity similarly to GATA2 mutation (mGATA2) in cells cotransfected with the Ednra−5.7;−4.2 construct or with specific mutated sites (mPRE6, mGATA2, and dmPRE6;GATA2) or missing all the PRE elements (ΔPRE1;PRE6). However, the siRNA failed to decrease further the activity in cells transfected with the mGATA2 vector or in cells transfected with the ΔPRE1;PRE6 construct compared with the dmPRE6;GATA2 control. Control cells were cotransfected with the scrambled control siRNA with the exception of the cells transfected with the dmPRE6;GATA2 vector. Two-way ANOVA: #, P < .001; *, P < .01; ^^, P < .05; ns, not significant. Error bars represent SEs.