The NF-kB-binding site is critical for the promoter activity of 6MIEp. (A) To investigate the importance of the NF-κB-binding site for the promoter activity of 6MIEp, a 5'-deletion mutant of the 6MIEp lacking the NF-κB-binding site (white letters in black box) was constructed. (B) The Luciferase assay was performed in various cell lines. The mean fold-activity relative to that of the blank pGL3-basic plasmid is indicated by the horizontal bars. The standard deviation for three independent experiments is indicated.