Figure 1
From: Antagonistic autoregulation speeds up a homogeneous response in Escherichia coli
The mar circuit regulates the response of Escherichia coli to a number of toxic compounds, including antibiotics.
It consists of a dual autogenous control motif constituted by an activator (MarA; acting as a monomer), and a repressor (MarR; acting as a dimer that can be inactivated by several compounds, e.g., salicylate). In more general terms (inset), the motif represents a combination of a strong (continuous line) negative and weak (dashed line) positive feedback loops. This motif is unique in the transcriptional regulatory network of E. coli.
