Expression of the PrrF RNAs is repressed by the ferric uptake regulator (Fur) when cells are grown in iron-replete conditions.

Under iron limitation, the PrrF RNAs are expressed and act to negatively regulate several genes encoding iron-containing proteins, including SodB and succinate dehydrogenase.

The phenomenon is mediated by PrrF repressing the expression of enzymes that degrade anthranilic acid, which is the precursor for PQS synthesis.

The PrrF RNAs of P. aeruginosa are unique from other Pseudomonas species, in that they are encoded by two highly homologous genes, prrF1 and prrF2, which are located in tandem on the chromosome.

Both homologues inhibit translation of antR mRNA, which affects quorum sensing and virulence factor production.