FIG. 2.

Relative expression levels of whiB1 to whiB7 following antibiotic stresses. Total RNA was isolated from M. tuberculosis (CDC1551) cultures (OD₆₀₀, 0.4) after treatment with ethambutol, isoniazid, cycloserine, streptomycin, and kanamycin for 3.5 h. Real-time quantitative RT-PCR was performed, and the relative expression level of each whiB gene was calculated using the sigA transcript for normalization for RNA amounts and untreated cultures as a control. Data shown are averages from four independent experiments.