Fig. 8

Model of gene regulation via XreR1 and XreR2. XreR1 binds to its own promoter, most probably leading to a positive feedback loop. Furthermore, it represses the expression of xreR2 and thereby maintains the 1° phenotype. XreR2 in turn binds to XreR1 thereby putatively re-enforcing its own expression. The XreR1-XreR2 complex might directly represses 1°-specific features inducing the 2° phenotype. Additionally, XreR2 most probably activates expression of the TAS-derived ccdAB-like system which could maintain the 2° phenotype by activating 2°-specific features. Green: activation; red: inhibition