FIG. 3.

Effect of eukaryotic transcriptional blockers on HO-1 mRNA induction by R. rickettsii. EC were incubated in the presence (+) or absence (−) of actinomycin D (0.25 μg/ml) and α-amanitin (5.0 μg/ml) for 30 min prior to and during a 4-h infection with R. rickettsii. Control cells were exposed to vehicle alone. Northern blots probed with a human HO-1-specific cDNA and the probe for the housekeeping gene, GAPDH, are shown. The results shown are representative of three independent experiments.