Figure 7. hp_0350 promoter activity is affected by the A-tract located adjacent to the −35 promoter element.

A) Effects on hp_0350 and pyrG promoter activities by the length of the repeat tract located in their divergent promoter regions (A₁₄/T₁₄ [wt] vs. A₉/T₉ [Δ₅]). Strains were grown in Brucella broth at 37°C in 24-well plates under microaerophilic conditions Expression from the hp_0350::lacZ and pyrG::lacZ reporters in strain SMI109 shown are from samples collected in logarithmic growth phase (OD₆₀₀ of 0.2, Fig. S7A). Illustration shows the position of the repeat tract, relative to the −35 elements, of each gene. DNA sequence alignment of the hp_0350/pyrG promoter regions from 45 different strains is shown in Fig. S9. B) In silico DNA structure predictions of the hp_0350, hofA (HP_0209) and hopM (HP_0227) promoter regions based on sequences from strain 26695. The analysis were performed as in Fig. 6A. Images in the left panel show DNA structures with wt tract lengths, and in the right panel, the structures of promoter DNA with 5 nucleotide shorter repeat tracts.