CsrB/RsmB RNA family

The CsrB RNA is a non-coding RNA that binds to approximately 18 copies of the CsrA protein. Although CsrA proteins are found in a wide variety of bacteria, CsrB RNAs are only known in enterobacter. The CsrB RNAs contain a conserved motif CAGGXXG that is found in up to 18 copies and has been suggested to bind CsrA. The Csr regulatory system has a strong negative regulatory effect on glycogen biosynthesis, glyconeogenesis and glycogen catabolism and a positive regulatory effect on glycolysis. In other bacteria such as Erwinia caratovara the RsmA protein has been shown to regulate the production of virulence determinants, such extracellular enzymes. RsmA binds to RsmB regulatory RNA which is also a member of this family.