Another ` Fur-activated 
the small regulatory RNA ryhB is responsible for the Fur-mediated regulation of several genes relevant to this study
The involvement of several Fur-regulated , iron response genes ( entE , entF , fes and gpmA ) in NE-enhanced growth and the altered expression of the hfq gene , encoding an RNA chaperone required for stability of several small antisense regulatory RNAs including RyhB [ 23 ] suggested that the ryhB gene may also be differentially expressed in the presence versus absence of norepinephrine : a 13-fold decrease in transcription was observed for the small regulatory RNA during norepinephrine exposure .
Thus , ryhB transcription is dependent on regulation by the Fur protein in response to iron availability .