Fig. 2.

(A) Influence of a pup deletion on global gene expression under iron-limitation conditions. The transcriptional network controlling iron homeostasis in C. glutamicum involves the Fe²⁺-sensing master regulator DtxR and the AraC-type regulator RipA. Under iron-replete conditions, DtxR is complexed with Fe²⁺, and only then does it bind to its target promoters. The boxes show those DtxR and RipA target genes, whose mRNA ratio was changed at least twofold in a transcriptome comparison of the Δpup mutant and the WT under iron-limitation conditions. A list of all genes showing differential expression in the Δpup mutant is given in Table S2. (B) Comparison of ripA promoter activity in C. glutamicum WT (black) and the Δpup mutant (red) using the reporter plasmid pJC1-PripA-crimson. The two strains were cultivated under iron limitation, and samples were taken after 0, 2, 4, 6, and 24 h. A total of 100,000 cells of each sample were analyzed by flow cytometry for Crimson fluorescence. Two biological replicates were performed, and error bars indicate the deviation between the samples. Scatter plots of the samples are shown in Fig. S9.