Identification of Corynebacterium diphtheriae iron- and DtxR-regulated genes

Corynebacterium diphtheriae serves as an important model system for studying iron-dependent gene regulation in Gram-positive bacteria. This study sought to further characterize the iron and Diphtheria Toxin Repressor (DtxR) regulons in C. diphtheriae, since previous studies had only identified individual regulated genes rather than conducting systematic genome-wide analysis. The investigation revealed that iron and DtxR function in both gene repression and activation. Beyond the established role in repressing target gene expression, iron and DtxR were found to induce expression of multiple genes, some of which are thought to be controlled by the RipA transcriptional repressor. The identified iron-regulated genes control critical virulence factors including iron acquisition systems and putative iron-stress tolerance mechanisms, which are essential for bacterial survival and pathogenicity. The comprehensive characterization of DtxR's diverse regulatory roles expands fundamental understanding of bacterial iron homeostasis and global gene regulation mechanisms.