Figure 5.

Activation of ERβ by E₂ represses the activity of the hUcn promoter through the region containing a CRE site. A, PC12 cells were cotransfected with PGL2-hUS2 or deleted mutants of the hUcn promoter and pcDNA-ERβ. The results are expressed relative to vehicle (100%). Luciferase activity corresponds to light units of firefly luciferase normalized to renilla luciferase light units. B, PC12 cells were cotransfected with the −161 promoter and pcDNA-ERβ and treated for 24 h with 10 nm E₂ and/or 0.5 mm 8-Br-cAMP. Vehicle (V) in B corresponds to ethanol plus DMSO used to E₂ and 8-Br-cAMP, respectively. All of the treatment conditions have the same concentration of each vehicle. Luciferase activity corresponds to light units of firefly luciferase normalized to total protein. Values are the mean ± SEM of two to three independent experiments. Statistical analysis by ANOVA followed by Dunn post hoc test gave the following significances: ★, p < 0.001, ✚, p < 0.01, and •, p < 0.05, compared with respective vehicle control; ×, p < 0.05, compared between them.