Fig. 2: Schematic representation of an E. coli K-12 MG1655 E. coli cell with the relevant elements.

Shown is the chromosome of, origin of replication (oriC), terminator of replication (terC) and phage λ integration site (attB). A graphic representation of the organization of the modules at the insertion site is indicated below. During normal growth, the Pfrr promoter is weak, but constitutively active, while the stress promoters are switched off (left). After a challenge with a suitable stressor, the stress-related promoter becomes activated (right).