Elucidating the Regulon of a Furlike Protein in subsp. ().

Intracellular iron concentration is tightly regulated to maintain cell viability. Iron plays important roles in electron transport, nucleic acid synthesis, and oxidative stress. A subsp. ()-specific genomic island carries a putative metal transport operon that includes , which encodes a Fur-like protein. Although well characterized as a global regulator of iron homeostasis in multiple bacteria, the function of Fur (ferric uptake regulator) in is unknown as this organism also carries IdeR (iron dependent regulator), a native iron regulatory protein specific to mycobacteria. Computational analysis using PRODORIC identified 23 different pathways involved in respiration, metabolism, and virulence that were likely regulated by . Thus, chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) was performed to confirm the putative regulon of (Fur-like protein) in . ChIP-Seq revealed enriched binding to 58 regions by Fur under iron-replete and -deplete conditions, located mostly within open reading frames (ORFs). Three ChIP peaks were identified in genes that are directly related to iron regulation: (hemophore-like protein), (Fur box), and (ABC transporter). Fur box consensus sequence was identified, and binding specificity and dependence on Mn availability was confirmed by a chemiluminescent electrophoresis mobility shift assay (EMSA). The results confirmed that is a Fur ortholog that recognizes a 19 bp DNA sequence motif (Fur box) and it is involved in metal homeostasis. This work provides a regulatory network of Fur binding sites during iron-replete and -deplete conditions, highlighting unique properties of Fur regulon in