Control of Fur synthesis by the non-coding RNA RyhB and iron-responsive decoding.
The Fe2+-dependent Fur protein serves as a negative regulator of iron uptake in bacteria. As only metallo-Fur acts as an autogeneous repressor, Fe2+scarcity would direct fur expression when continued supply is not obviously required. We show that in Escherichia coli post-transcriptional regulatory mechanisms ensure that Fur synthesis remains steady in iron limitation. Our studies revealed that fur translation is coupled to that of an upstream open reading frame (uof), translation of which is downregulated by the non-coding RNA (ncRNA) RyhB. As RyhB transcription is negatively controlled by metallo-Fur, iron depletion creates a negative feedback loop. RyhB-mediated regulation of uof-fur provides the first example for indirect translational regulation by a trans-encoded ncRNA. In addition, we present evidence for an iron-responsive decoding mechanism of the uof-fur entity. It could serve as a backup mechanism of the RyhB circuitry, and represents the first link between iron availability and synthesis of an iron-containing protein.
Vecerek
Branislav
B
Department of Microbiology and Immunobiology, Max F Perutz Laboratories, University of Vienna, Vienna, Austria.
Moll
Isabella
I
Bläsi
Udo
U
D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D020029:Base Pairing; D001483:Base Sequence; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D025461:Feedback, Physiological / Q000235:genetics / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D007501:Iron / Q000378:metabolism*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics
D001426:Bacterial Proteins; D017931:DNA Primers; D022661:RNA, Untranslated; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D007501:Iron