Figure 3.
Induction of the D1–96 promoter by estradiol requires the presence of wild-type ER and integrity of the CRE-binding site. (A) HeLa cells were transfected with D1–96 Luc, pSG5-ER, and pCH110 as described in Fig. 2B. After 24 h, cells were incubated with 10 nM estradiol and/or 100 nM tamoxifen, and/or 5 nM ICI 182,780 or ethanol vehicle for 24 h. (B) Deletion mutants of the ER were transfected with D1–96 Luc and pCH110. After 24 h cells were incubated with 10 nM estradiol or ethanol vehicle for 24 h. (C) Effect of CRE mutation (Inset) on the activation of the D1–96 promoter by ER. The pSG5-ER was cotransfected with D1–96 Luc or with D1–96m Luc and pCH110 in HeLa cells. After 24 h, cells were incubated with 10 nM estradiol for 24 h. At 48 h posttransfection cells were harvested and luciferase activities were measured and normalized to β-galactosidase activities.