Figure 3.

Differential gene regulation by AdcR. Strain MGAS10870 was grown to late exponential phase (A₆₀₀ ∼ 1.0) in zinc-rich growth medium and treated with 50 μM TPEN. Samples were collected at one-minute intervals for 5 min. Transcript levels of phtD (A) and adcC (B) were measured by qRT-PCR. Three biological replicates were used. Data graphed are mean ± standard deviation. Average values for untreated samples were used as reference and the fold changes in the transcript levels in the treated samples relative to untreated sample were shown above. The sensitivity of AdcR bound to two- (C) and one-site (D) operator sequences to zinc chelation was assessed by gel mobility shift assay. The metallated form of AdcR bound to DNA was challenged by increasing concentrations of TPEN (45, 55, 60, 65, 70, 75, 80 and 100 μM) and the reaction mixtures were resolved on a 10% native PAGE. Representative image from three independent experiments is shown. The positions of free (F) and AdcR-bound (B) forms of probe are indicated.