Activation of ERα by E2 and T increases the activity of the hUcn promoter through a promoter region containing half-ERE, Sp1, and Ap1 sites. PC12 cells were cotransfected with the hUcn promoter (pGL2-hUS2) or deleted mutants and pcDNA-ERα. The results are expressed relative to vehicle (100%). Luciferase activity corresponds to light units of firefly luciferase normalized to renilla luciferase light units. 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. Analysis by Mann–Whitney U test gave the following significance: ★★★, p < 0.001, compared with respective vehicle control.