Figure 1.

The scaffold design. The three reporters are controlled by promoters responsive to: tetracycline/aTc (cfp), lactose/IPTG (yfp), and both lactose/IPTG and arabinose/L-ara (rfp). Terminators are blue boxes denoted "T," RBSs are small purple circles, unique restriction sites are blue dashed-arrows, and promoters are small black arrows. Each fluorescent operon is shown as a colored block arrow, while the kanamycin antibiotic resistance is shown as a white block arrow. The three transcription factors TetR, LacI, and AraC are shown regulating the three fluorescent genes in a simple genetic network: TetR represses cfp, LacI represses both rfp and yfp, and AraC activates rfp. The scaffold sequence is in Additional File 1.