Heme is an abundant source of iron in the human host, and may serve as a signal to bacterial pathogens, such as P. aeruginosa, to induce virulence gene expression. While all Pseudomonads encode for the iron-regulated PrrF RNAs, only P. aeruginosa encodes for the heme responsive PrrH RNA. As P. aeruginosa is the sole human pathogen in this genus, we hypothesize that heme regulation via PrrH plays a critical role in virulence. The unique sequence of the PrrH sRNA of P. aeruginosa was previously shown to allow for regulation of genes distinct from those in the PrrF regulon (Oglesby-Sherrouse & Vasil, 2010). Alexandria has identified additional targets of PrrH and is studying how heme regulation of these targets contributes to pathogenesis in P. aeruginosa.
Reinhart AA, Powell DA, Nguyen AT, O’Neill M, Djapgne L, Wilks A, Ernst RK, Oglesby-Sherrouse AG. (2015) The prrF-encoded small regulatory RNAs are required for iron homeostasis and virulence of Pseudomonas aeruginosa. Infection and Immunity 83(3):863-875.