FIG. 8.

Synergistic effect of TCDD signaling and NFI/CTF. (A) Structure of the promoter driving the reporter gene in the pXRE3G5-FL plasmid. (B) Cells were transfected with the pXRE3G5-FL reporter vector (2.5 μg) and with 3 μg of either pRSV.Gal.CTF, pRSV.Gal.Sp1, pRSV.Gal.Oct (see the Materials and Methods section), or pRSV/MCS. All cells were cotransfected with pαglob-RL (1 μg) as an internal control. Cells were left untreated or treated with TCDD (3 nM, and/or H₂O₂ (50 μM) for 16 h. Results were expressed as means ± standard errors of the means for the quotient of firefly luciferase activity and Renilla luciferase activity (n = 9), normalized to 100% for cells transfected with pRSV/MCS and treated with TCDD. For each Gal fusion, statistical differences between TCDD-treated cells treated with H₂O₂ (50 μM) and cells not treated are marked with a double asterisk (P < 0.0001).