FIG. 5.

AP1 EMSA. Nuclear extracts from noninfected cells (Non) and cells infected for 40 min with PA103 (WT) or PA103 exoU (U-) were incubated with radiolabeled AP1 oligonucleotide. An intense shifted band (arrow) indicates the presence of active DNA-binding AP1 complex. Competition experiments with 10- and 50-fold excess unlabeled (AP1 comp) AP1 oligonucleotide abolished the band, whereas nonspecific oligonucleotide (non-specific comp) did not, indicating the specificity of the DNA-protein complex. Inclusion of anti-c-Fos antibody, but not anti-β-galactosidase (anti-β-Gal) antibody, inhibited band formation, indicating that c-Fos protein was present in the active complex.