Feedback control of the pleiotropic regulators and H-NS antagonists LeuO and RcsB-BglJ in Escherichia coli

The enterobacterial LeuO protein emerged as a pleiotropic transcriptional regulator important in pathogenicity and stress adaptation. Intriguingly, regulation of the H-NS repressed leuO gene involves a double-positive feedback loop. The leuO gene is activated by the RcsB-BglJ heterodimer, and vice versa LeuO activates expression of bglJ, encoded within the H-NS repressed yjjQ-bglJ operon. Further data suggest that the double-positive feedback loop built by LeuO and RcsB-BglJ is tightly controlled. The aim of the project is to describe the regulatory elements of the LeuO and RcsB-BglJ control circuit, which is likely to be important in the response to specific, virulence-related environments.