Iron and Fur gene regulation by an opportunistic pathogen. Aggregatibacter actinomycetemcomitans strain:624

One of the most important strategies by the host innate immune system is to restrict the access of pathogens to iron, an essential nutrient. The goal of this study was characterize the low-iron and Fur regulons of Aggregatibacter actinomycetemcomitans (Aa), an opportunistic pathogen that causes oral cavity and abscess infections. The low-iron regulon is the set of genes differentially expressed in response to iron restriction, and was characterized by high-throughput RNA-sequencing (RNA-seq) of Aa biofilms grown on rich and low-iron media. The Fur regulon is the set of genes controlled by the bacterial iron sensor Ferric Uptake Regulator (Fur), and was characterized by a combination of RNA-seq of an Aa fur- mutant, to identify genes both directly and indirectly controlled by Fur, and chromatin immunoprecipitation (ChIP)-sequencing of Fur in Aa grown in vitro and in vivo in murine abscesses, to identify genes directly controlled by Fur in laboratory and host environments.