FIG 2.
RipR is necessary and sufficient to induce PIRO expression in response to itaconate. Expression of PIRO-sfGFP in wild-type (WT) or ripR knockout (ΔripR) Salmonella or in E. coli. Figures show GFP fluorescence normalized to optical density at 600 nm (OD600) after 16 h of growth in LB alone or supplemented with 0.2% itaconate (A) or similar metabolites (B). Data are the averages from at least three biological replicates, and error bars show one standard deviation. pPIRO, plasmid-borne transcriptional fusion of PIRO to sfGFP; pRipR-PIRO, pPIRO with the ripR gene and its native promoter included on the plasmid. A Games-Howell analysis of variance (ANOVA) was conducted comparing with and without itaconate for each strain (A) or comparing WT to ΔripR (B) for each added metabolite. *, P < 0.05; **, P < 0.01; ***, P < 0.001.