Figure 7.

Interaction with the distal, polyA-binding face of Hfq is critical for Rho inhibition. (A) Effect of polynucleotides (concentrations in nucleotides are indicated above gel lanes) on Hfq-mediated transcription antitermination at λtR1 in the presence of 70 nM Rho. In vitro transcriptions were performed with the pT7A1-λcro template (Figure 2A) and Hfq (+ lanes) present at a concentration of 210 nM. Global termination efficiencies (Term) are indicated below gel lanes. (B) Effect of the polynucleotides (900 nM, in nucleotides) on Rho-directed unwinding of the tR1RNA/D₂₁ duplex. The concentrations of Rho and Hfq (in selected samples) were 20 nM and 210 nM, respectively. (C) Oligomer rA₂₀ prevents the association of Hfq with the binary Rho–dC₃₄ complex. Assay conditions are as in Figure 5B. Concentration of Hfq was 375 nM. (D) Oligomer rA₂₀ does not displace Hfq from tR1RNA whereas poly[rA] does.