title: Mutual regulation of Crl and Fur in Escherichia coli W3110.
abstract: The small regulatory protein Crl controls the expression of curli. Recently we have shown that Crl interacts directly with one of the most global regulators of Escherichia coli, the stress-related sigma factor RpoS, suggesting a more global role for Crl. We show here by a proteomics analysis that the expression of at least nine cellular proteins was considerably modified when Crl was overexpressed. We assessed the part of transcriptional and post-transcriptional regulation for five of these genes. The results showed that Crl regulates the expression of another global regulator, the central regulator of iron homeostasis, Fur. A molecular analysis revealed that Crl and Fur affect their own and each other's expression. We provide physical evidence for the binding of Fur to the crl and fur promoter regions. Crl modulated the affinity of Fur at the fur promoter but not at the crl promoter. The triad RpoS-Crl-Fur may thus represent the centerpiece of a global regulatory system of response to different stresses.
authors.affiliation: Laboratoire Adaptation et Pathogénie des Microorganismes, Institut Jean Roget, Domaine de la Merci, Université Joseph Fourier, BP 170, 38042 Grenoble Cedex 9, France. cecile.lelong@ujf-grenoble.fr
authors.forename: Cécile
authors.initials: C
authors.lastname: Lelong
authors.forename: Magali
authors.initials: M
authors.lastname: Rolland
authors.forename: Mathilde
authors.initials: M
authors.lastname: Louwagie
authors.forename: Jérôme
authors.initials: J
authors.lastname: Garin
authors.forename: Johannes
authors.initials: J
authors.lastname: Geiselmann
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D048168:Escherichia coli K12 / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D009154:Mutation; D040081:Protein Array Analysis; D040901:Proteomics; D012097:Repressor Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; C077481:Crl protein, Bacteria