Figure 4 |. cis-regulatory architecture of the promoter deoCp2.

The line represents the deoCp2 promoter along with its transcription factor regulatory sites (TFRS). –35 and –10 elements and transcription start site (TSS; +1) are labelled, and the cis-regulatory architecture is represented by transcription factors (TFs; bubbles) bound to their corresponding TFRS. a | Cooperative regulatory interaction between CRP and CytR in the deoCp2 promoter. CytR is recruited as a corepressor by pre-bound CRP²²¹. Since CytR necessarily requires pre-bound CRP to repress expression of the transcription unit downstream, these four sites form a TFRS module²²². b | The TFRS collection of promoter deoCp2 is the complete set of TFRS known to regulate the deoCp2 promoter. Although there might be indirect regulatory interactions among DeoR, ModE, Fis, CRP and CytR, the only direct and necessary interaction is the one between CytR and CRP^223–225. The other TFs act independently under different conditions on deoCp2, each with their own proximal sites.