Single Cell Kinetics of Phenotypic Switching in the Arabinose Utilization System of E. coli
Figure 1
Scheme of the arabinose utilization system in E. coli.
Arabinose is imported via the arabinose transporters AraE and AraFGH. If the intracellular arabinose level is sufficiently large, arabinose binds the transcriptional regulator AraC. This complex activates the promoters PE, PFGH, PBAD and PJ, driving expression of araE, araFGH, araBAD and araJ, respectively. The latter two operons encode proteins for arabinose catabolism (AraBAD) and a putative arabinose efflux pump (AraJ). The negative autoregulation of AraC resulting in homeostatic control of its own level is not shown explicitly. Arrows indicate arabinose transport and positive regulation, whereas the T-shaped arrow indicates arabinose metabolization.