Figure 7.
Robustness and non-robustness of other OmpR targets. (A) The same RNA samples used in Figure 4D were analyzed by northern blot probed for ompF and for SsrA as a loading control. (B) MicF sRNA is involved in the post-transcriptional control of ompF upon OmpR overproduction. The β-galactosidase activity of Ptet-ompF-lacZ translational fusion was measured with and without IPTG induction of ompR overexpression in micF+ and micF− cells (strains MG2127 and MG2167 respectively). (C) bolA mRNA levels were analyzed by northern blot in strains MG1004 (wt) transformed with pHDB3 or pOmpR, MG1811 (ΔompR) transformed with pHDB3 and in MG2000 (Tet-Plac-ompR) with or without IPTG. SsrA levels were probed as well and used as a loading control. (D) Expression of a dtpA-lacZ promoter fusion was followed in a set of strains with various OmpR levels (MG2138 (wt), MG2169 (ΔompR) and MG2170 (Tet-Plac-ompR)).