PrrB/RsmZ RNA family
The PrrB/RsmZ RNA family are a group of related non-coding RNA molecules found in bacteria. PrrB RNA is able to phenotypically complement gacS and gacA mutants and is itself regulated by the GacS-GacA two-component signal transduction system. Inactivation of the prrB gene in "Pseudomonas fluorescens" F113 resulted in a significant reduction of 2, 4-diacetylphloroglucinol (Phl) and hydrogen cyanide (HCN) production, while increased metabolite production was observed when prrB was overexpressed. The prrB gene sequence contains a number of imperfect repeats of the consensus sequence 5′-AGGA-3′, and sequence analysis predicted a complex  secondary structure featuring multiple putative stem-loops with the consensus sequences predominantly positioned at the single-stranded regions at the ends of the stem-loops. This structure is similar to the CsrB and RsmB regulatory RNAs (CsrB/RsmB RNA family), suggesting this RNA also interacts with a CsrA-like protein. Studies in "Legionella pneumophila" have shown that the ncRNAs RsmY and RsmZ together with the proteins LetA and CsrA are involved in a regulatory cascade. Also, it appears that these ncRNAs are regulated by RpoS sigma-factor.