Abundance of RgtA is affected by the Hfq protein and phenotypic modulation. (A) Northern blot analysis was performed using total RNA isolated from Tohama I strain (lane 1) and its isogenic Δhfq mutant (lane 2) probed with biotinylated probes specific to RgtA (upper panel) and to SsrA RNAs (lower panel, loading control). Only relevant parts of the membranes are shown. The result is a representative of three independent experiments. (B) B. pertussis Tohama I strain was grown in SS medium in the absence or presence of magnesium sulfate (lanes 1,2) and nicotinic acid (lanes 3,4) for 2 h. In another experiment, Tohama I cells were grown in parallel at 37°C and 22°C for 48 h in SS medium (lanes 5,6). At these time points cells were harvested and isolated RNA was probed with biotinylated RgtA-specific probe and subjected to northern blot analysis (upper panels). Signals obtained upon rehybridization of the membrane with SsrA-specific probe (lower panels) served as loading control. Only relevant parts of the membranes are shown. The result is a representative of four experiments. (C) B. pertussis Tohama I strain (lane 1) and its isogenic mutants carrying deletions of bvgA (lane 2), bvgS (lane 3), bvgR (lane 4), ΔrisA (lane 5), and ΔrisAΔbvgR (lane 6) genes were grown in SS medium to exponential phase. RNA isolated from harvested cells was probed with biotinylated RgtA-specific probe and subjected to northern blot analysis. Signals obtained upon rehybridization of the membrane with SsrA-specific probe (lower panels) served as loading control. Only relevant parts of the membranes are shown. The result is a representative of three experiments.
