FIG. 2.

Effect of rifampin (Rif.) on NF-κB activation. (a) Effect of rifampin on IκB degradation by Western blot analysis of IκB expression in A549 cells stimulated with IL-1ß, TNF-α, and IFN-γ (Mix; 100 ng/ml each) in the presence or absence of rifampin (50 μg/ml). Cytosolic extracts were prepared at the indicated times. Similar results were obtained in three similar experiments. (b) Densitometric analysis of the blot presented in panel a. C′, control. (c) EMSA for NF-κB activation. Equivalent nuclear extracts prepared from cells 2 h after stimulation with IL-1ß, TNF-α, and IFN-γ (Mix) with or without rifampin (50 μg/ml) were assayed for binding activity with an oligonucleotide-containing the NF-κB consensus sequence. Specific DNA binding complexes were identified by competition with unlabeled probe (lane 4). Lane 1, labeled probe alone. (d) Results of densitometric analysis from three experiments.