Fig. 3.

CsrA^crw alleles inhibit motility and filament assembly. (A) Quantitative swarm expansion assays for strains: WT (○, 3610), and P_hyspank-csrA in the presence of 1 mM IPTG (●, DS4940). (B) Quantitative swarm expansion assays for strains: ΔcsrA P_hyspank-csrA in the presence of 1 mM IPTG (□, DK1522) and ΔfliWcsrA P_hyspank-csrA in the presence of 1 mM IPTG (■, DK1469). (C) Quantitative swarm expansion assays for strains: P_hyspank-csrA^R6L in the presence of 1 mM IPTG (▲, DK1616) and ΔcsrA P_hyspank-csrA^R6L in the presence of 1 mM IPTG (△, DK3713). Note that the allele presented in C is a lof for RNA binding, but not FliW binding, and thus ectopic expression of the allele partially inhibits motility by titrating FliW from WT protein expressed from the native locus. (D) Quantitative swarm expansion assays for strains: ΔcsrA P_hyspank-csrA^I14M in the presence of 1 mM IPTG (♢, DK3004) and ΔcsrA P_hyspank-csrA^N55D in the presence of 1 mM IPTG (♦, DK3005). Each point is the average of three replicas. (E) Fluorescence micrograph overlays of WT (DS9502), ΔcsrA P_hyspank-csrA^N55D (DK2442), and ΔcsrA P_hyspank-csrA^I14M (DK2441) in the presence of 1 mM IPTG, membrane stained with FM4-64 (false colored red) and flagella stained (false colored green). (Scale bar, 2 µm.)