Hfq is involved in σE-mediated post-transcriptional regulation. (A) The effect of σE on Hfq expression in LB log, LPM 4h, and LPM 20h conditions. Western blots of Hfq-2HA in protein extracts from WT and ΔrpoE strains in the three conditions studied. DnaK was used as loading control. For quantification, the ratio of Hfq/DnaK was relative to the WT background in LB log condition (arbitrarily set to 100). (B) Venn diagrams showing transcripts and proteins regulated by Hfq in LB log, LPM 4h, and LPM 20h conditions. (C) Venn diagrams comparing post-transcriptional regulons of σE and Hfq. (D) Western blots of SodC2–2HA and PspA–2HA in protein lysates from WT, ΔrpoE strain, and ΔrpoE strain complemented with Hfq-expressing plasmid in LPM 4h condition. DnaK was used as loading control. For quantification, the ratio of SodC2/DnaK or PspA/DnaK was relative to the WT background.