Inhibition of BCO1 promoter activity by dexamethasone.

<p><b>A</b>. <i>Above</i>, a schematic diagram of the BCO1 promoter reporter gene (pGL3-BCO1022-Luc) showing the location of putative transcription factor binding sites. <i>Below</i>, A549 cells were transiently transfected with 1 μg of pGL3-BCO1022-Luc plus 0.2 μg of pCMV-β-Gal vector as a control for transfection efficiency. After 16 h transfection, cells were treated with EtOH (Vehicle), DEX (10⁻⁷ M) or forskolin (FSK, 10⁻⁵ M) for 20 h. Luciferase and β-Gal activities were measured and relative-fold luciferase activity (compared to pGL3-Basic transfection) was determined after adjustment for β-Gal activity. Results are presented as means ± S.D. of three independent experiments, each performed in triplicate; * <i>P</i><0.05; ** <i>P</i><0.01. <b>B</b>. A549 cells were transiently transfected with 1.0 μg/well of luciferase reporter construct containing either the <i>bco1</i> gene proximal 218 bp promoter (pGL3-BCO218-Luc) or with corresponding mutated sequences, as indicated. After transfection for 16 h, cells were treated in the presence or absence of DEX (10⁻⁷ M) for 20 h. Luciferase and β-Gal activities were measured and relative-fold luciferase activity (compared to pGL3-basic) was determined after adjustment for β-Gal activity. Results shown are means ± S.D. of three or more independent experiments, each performed in triplicate. * <i>P</i>< 0.05; ** <i>P</i>< 0.01.