Mathematical Modeling: Bridging the Gap between Concept and Realization in Synthetic Biology
Figure 7
Design concept for the repressor-activator system in Guido et al. [8]. The repressor-activator system was assembled by combining (a) an unregulated system base with (b) a repressor-only module and (c) an activator-only module. The unregulated system consists of an promoter driving GFP expression. The rectangular boxes in the promoter are the binding sites for the lacI and cI proteins. The cross at indicates a point mutation that inhibits cI binding at this site. In (b), the repressor-only module, the promoter controls the transcription of lacI, which binds to the site to repress the promoter. The extent of this effect can be tuned by using the lacI inhibitor IPTG, which reduces the binding of lacI protein to the site. In (c), the activator-only module, the promoter controls the transcription of cI, which can bind to either the 1 or the 2 sites, sequentially or cooperatively, to activate the promoter. The extent of this effect can be tuned through arabinose, which activates the promoter (adapted from Guido et al. [8]).