IHF increases specificity of activation by PspF and NRI. (A) NRI-dependent activation assayed on supercoiled templates (3 nm) containing the pspA promoter (pJD10), the glnH promoter (pJD37), and the glnAp2 promoter (pTH8) in the presence or absence of IHF. The specific transcripts generated from each of these templates are identified. (B) PspF-dependent activation assayed on supercoiled templates (3 nm) containing the pspA promoter (pJD10) and the glnH promoter (pJD37) in the presence or absence of IHF. (C) PspF-dependent activation assayed on supercoiled templates (3 nm) containing the pspAΔUAS promoter (pJD12) and the glnH promoter (pJD37) in the presence or absence of IHF. Quantified RNA transcripts (in decreasing order of size and in normalized arbitrary units): (A) (Lane 1) 0.61; 1.0, 0.75; (lane 2) 0.11, 1.6, 0.85; (B) (Lane 1) 1.0, 0.33; (lane 2) 1.8, 0.13; (C) (Lane 1) 1.0, 0.63; (lane 2) 0.29, 0.23.