Fig. 2.

STARs can interface with constitutive and inducible control elements to switch and tune regulatory properties. a STARs make constitutive gene expression elements switchable. Schematic DNA template of a library of target DNA plasmids containing variable strength promoters and ribosome binding sites (RBS). Fluorescence characterization of E. coli cells transformed with this library in the absence (left grid, -STAR) and presence (right grid, +STAR) of a plasmid encoding cognate STAR (raw data shown in Supplementary Fig. 13). b STARs tune inducible promoters. Schematic DNA template of a plasmid in which the plux promoter controls STAR production in response to acyl-homoserine lactone (AHL). Fluorescence characterization of E. coli cells transformed with this plasmid and a plasmid encoding a target RNA construct controlling sfGFP expression and exposed to a range of AHL concentrations. Changing the STAR:target pair in this configuration results in unique induction curves. Fluorescence characterization was performed by bulk fluorescence measurements (measured in units of fluorescence [FL]/optical density [OD] at 600 nm). Data represent mean values and error bars represent s.d. of n = 9 biological replicates