ERα regulates <i>CLOCK</i> promoter activity.

Abstract

<p>A, Schematic illustration of estrogen response elements in <i>CLOCK</i> promoter containing <i>CLOCK</i> sequence from −884 to +992 fused to luciferase (CLOCK-WT-Luc). B, Luciferase activity of HeLa cells transfected with CLOCK-WT-Luc and increasing amounts of REV-ERBα expression plasmid. C, Luciferase activity of HeLa cells transfected with CLOCK-WT-Luc plus REV-ERBα or ERα expression plasmids or both. D, Luciferase activity of HeLa cells transfected with CLOCK-WT-Luc and different amounts of ERα expression plasmid. E, Luciferase activity of HeLa cells transfected with CLOCK-WT-Luc and increasing amounts of ERβ expression plasmid. MCF-7 (F), T47D (G) and MDA-MB-231 (H) cells were grown in steroid-depleted media for 2 days, and then transfected with CLOCK-WT-Luc, followed by treatment with E2 or ICI alone or in combination. F-H, For control, cells were transfected with pGL3. pGL3 containing no <i>CLOCK</i> sequence was used as a mock DNA constructs. I, MCF-7 cells grown in normal media were transfected with the indicated shRNA (ERα; Con as a negative control) and CLOCK-WT-Luc. B-I, The graph depicts the normalized luciferase activity for each condition. Each experiment was performed in triplicate and repeated at least of three times. Data shown are the means ± SDs. <i>P</i> value was determined by ANOVA with Bonferroni test (*, <i>P</i><0.05. ns, not significant).</p