Fig. 6.

Progesterone blocks recruitment of the transcriptional activation complex at the promoter and enhancer of β-casein gene induced by PRL and glucocorticoids. HC-11 cells were transduced with 50 pfu/cell of adenovirus encoding hPR-B and then treated with ethyl alcohol (EtOH) (−control), R5020 (100 nm), HC (1 μg/ml), HC (1 μg/ml) + R5020 (100 nm), PRL (3 μg/ml) + HC (1 μg/ml), or PRL (3 μg/ml) + HC (1 μg/ml) + R5020 (R) at 100 nm for the indicated times (15 or 30 min). Cells were harvested and processed for ChIP assay as in Fig. 2 using antibodies to GR, C/EBPβ, p300, acetylated H3, and total RNA pol II. A, GR, C/EBPβ, p300, acetyl-H3, and RNA pol II interaction with the proximal promoter and distal enhancer. Graphical quantitation of the ChIP data from replicate experiments was performed as in Fig. 2. Values are averages ± sem from three independent experiments. B, Stat5a, PR, GR, C/EBPβ, p300, or RNA pol II interaction with the intervening region between the promoter and enhancer of β-casein (−3000 bp from the transcription start site). Gel insets are from a single representative experiment that was repeated three times.