Fig. 3.

CsrB signaling: Sequestration can bypass downstream delays. Error bars are SEM of duplicate measurements. (A) Experimental schematic. (B) Target expression turned on directly by turning on glgC-gfp transcription (IPTG added) or indirectly by turning on csrB transcription (aTc added). (C) Target expression turned off directly by turning off glgC-gfp transcription (IPTG removed) or indirectly by turning off csrB transcription (aTc removed). (D) GlgC-GFP expression as a function of percentage maximum csrB transcription (calibrated using PLtetO-1:st7:gfp; Fig. S2R). The gray shading indicates the regulatory range for CsrB. The open and closed circles are 100% and 0% of maximum [CsrB], respectively. *Incomplete silencing of GlgC-GFP expression occurs if the total [CsrA] is less than the total [target mRNA] or if there is “leaky” CsrB expression.