FIG. 5.

Binding of USF1 and USF2 to the E2 and E3 boxes in the hCYP19 promoter and first exon of hCYP19 gene is increased by proteasome inhibitors. Nuclear extracts from human cytotrophoblasts cultured in a 20% O₂ environment for 16 h in the absence or presence of proteasome inhibitors were incubated with ³²P-labeled oligonucleotides containing the E1, E2, and E3 boxes in the absence or presence of antibodies specific for USF1 and USF2 and analyzed by EMSA.