title: RpoE1, an extracytoplasmic function sigma factor, is a repressor of the flagellar system in Brucella melitensis.
abstract: The genome of Brucella melitensis contains genes coding for the sigma factors RpoD, RpoN, RpoH1, RpoH2, RpoE1 and RpoE2. Previously published data show that B. melitensis is flagellated and that an rpoE1 mutant overexpresses the flagellar protein FlgE. In this study, we demonstrate that mutation of rpoE1 causes an overexpression of the flagellar genes fliF, flgE, fliC, flaF and flbT, correlating with the production of a longer filament and thereby demonstrating that RpoE1 acts as a flagellar repressor. Moreover, mutation of rpoE1 increases the promoter activity of the flagellar master regulator ftcR, suggesting that RpoE1 acts upstream of ftcR. Together, these data show that RpoE1 represses the flagellar synthesis and filament length in B. melitensis.
authors.affiliation: Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Ferooz
authors.affiliation: Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Lemaire
authors.affiliation: Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Marie
authors.initials: M
authors.lastname: Delory
authors.affiliation: Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Xavier
authors.initials: X
authors.lastname: De Bolle
authors.affiliation: Unité de Recherche en Biologie Moléculaire (URBM), Facultés Universitaires Notre-Dame de la Paix Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Letesson
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017347:Brucella melitensis / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D021381:Protein Transport; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; D012808:Sigma Factor