Figure 8

Model of iron-triggered prophage induction. Under conditions of sufficient iron supply, the global iron regulator DtxR is in its (Fe²⁺-bound) active state and represses genes encoding high-affinity iron uptake systems while activating expression of ferritin³⁷. Under iron limiting conditions, DtxR dissociates from its target promoters and iron uptake is highly upregulated. A fast transition to medium containing high iron concentrations (e.g. 36 μM) will now lead to fast uptake of iron. Increased intracellular Fe²⁺ levels may cause oxidative stress and lead to SOS-triggered prophage induction in a fraction of cells (Figs 6 and 7).