FIG. 4.

IRF-3 transactivates the CXCL-8 promoter. (A) Huh7 cells were plated in 12-well plates and transfected with 0.5 μg of CMV-IRF-3 or vector plasmids along with 0.5 μg of the full-length −1481-luc CXCL-8 promoter-luciferase plasmid. Twenty-four hours later, cells were treated or not treated with 15 ng/ml of rhTNF-α for 6 h before luciferase activity was measured on cell lysates. The Western blot below the graphs depicts the expression of IRF-3 detected with polyclonal antiserum. Stat2 was also detected with polyclonal antiserum and served as a control for equal loading. Asterisks indicate significant stimulation of CXCL-8 transcription by IRF-3 compared to that of the vector control (*, P <0.01). RLU, relative light units. (B) Increasing amounts of IRF-3 were cotransfected with 0.5 μg of the synthetic CXCL-8 promoter, 2XISRE-luc, into Huh7 cells, and cells and lysates were processed as described above.