Increased expression of PprB under CSS is controlled by RpoS. (A) Promoter region of the pprB gene. Putative RpoS or PprB binding sites are framed or greyed. The ribosome binding site is shown in boldface and the translational start codon is underlined. (B) Expression values of pprB or ppprB-mut1 (RpoS binding sequence CTATATG was mutated to GGGTATG) transcriptional reporters in the wild-type, rpoS mutant, or PArpoS (ΔrpoS, rpoS complement at genomic attTn7 site) strains at exponential phase or after 5-h carbon deprivation. Expression values of pprB (C) or rpoS (D) transcriptional reporter under different stress conditions. (E) Expression values of flp, cupE, or rcpC transcriptional reporters in the PApprB2 (ΔrpoS, PprB overexpression) strain at exponential phase or after 5-h carbon deprivation. Data are from three independent experiments and shown as the means ± SDs. Statistical analysis was based on pairwise strain comparisons (t test). *, P < 0.05; **, P < 0.01, ***, P < 0.001; ns, not significant.