Transcriptional synergism between GATA4 and WT1 on the Amh promoter requires GATA4 and WT1 binding to their respective regulatory elements. A. The native -180 bp Amh promoter containing the GATA and WT1 elements in their natural context. B. A synthetic reporter containing two consensus GATA motifs upstream of the minimal Amh promoter with its WT1 binding site mutated. C. A synthetic reporter containing two consensus GATA motifs upstream of the minimal Amh promoter with an intact WT1 binding site. D. The minimal Amh promoter containing only a WT1 binding site. In all experiments, HeLa cells were co-transfected with the different promoter constructs (500 ng) along with an empty vector or expression vectors for the WT1(-KTS) (500 ng) and GATA4 (100 ng) used alone or in combination. All promoter activities are reported as fold activation over control ± S.E.M. Like letters indicate no statistically significant difference between groups (P > 0.05).