Two AP1 sites are essential for 1,2-NQ-induced IL-11 production.
A, schematic diagrams of reporter vectors, sequences of two AP-1 sites, and their mutants. B, HepG2 cells were transfected with a −1.3 kb reporter vector and then untreated or treated with 1,2-NQ in the absence or presence of U0126 (20 μm) for 18 h. Luciferase activities were calculated, and relative luciferase activities are expressed as -fold activation compared with unstimulated cells. Results are mean ± S.D. (error bars) of triplicate samples. ***, p < 0.001 versus 1,2-NQ-treated cells in the absence of U0126. C, HepG2 cells were transfected with the indicated reporter vectors and then stimulated and analyzed as in B. ***, p < 0.001 versus 1,2-NQ-treated cells transfected with the −1.3 kb reporter vector. D, HepG2 cells were transfected with the indicated reporter vectors and stimulated with the indicated concentrations of 1,2-NQ and then analyzed as in B. ***, p < 0.001; ns, not significant versus untreated cells transfected with each reporter vector.