RyhB

RyhB RNA is a 90 nucleotide RNA that down-regulates a set of iron-storage and iron-using proteins when iron is limiting; it is itself negatively regulated by the ferric uptake repressor protein, Fur (Ferric uptake regulator).

[4] A number of other genes have been predicted computationally and verified as targets by microarray analysis: napF, sodA, cysE, yciS, acpS, nagZ and dadA.

A comparative genomics target prediction approach suggests that the mRNAs of eleven additional iron containing proteins are controlled by RyhB in Escherichia coli.

Two of those (erpA, nirB) and two additional targets that are not directly related to iron (nagZ, marA) were verified with a GFP reporter system.

In this capacity it may act both as an RNA-RNA interaction based regulator and as a transcript encoding for a small protein.

Secondary structure for the RyhB RNA. The Sm-like protein Hfq binds to the AU-rich unstructured region of RyhB as indicated. Below the secondary structure, the primary sequence of RyhB is shown along with its putative binding interaction to the target mRNA sodB. The start codon for sodB is underlined. RyhB nucleotides that participate in the interaction are in bold. [ 1 ]