title: Brucella melitensis MucR, an orthologue of Sinorhizobium meliloti MucR, is involved in resistance to oxidative, detergent, and saline stresses and cell envelope modifications.
abstract: Brucella spp. and Sinorhizobium meliloti are alphaproteobacteria that share not only an intracellular lifestyle in their respective hosts, but also a crucial requirement for cell envelope components and their timely regulation for a successful infectious cycle. Here, we report the characterization of Brucella melitensis mucR, which encodes a zinc finger transcriptional regulator that has previously been shown to be involved in cellular and mouse infections at early time points. MucR modulates the surface properties of the bacteria and their resistance to environmental stresses (i.e., oxidative stress, cationic peptide, and detergents). We show that B. melitensis mucR is a functional orthologue of S. meliloti mucR, because it was able to restore the production of succinoglycan in an S. meliloti mucR mutant, as detected by calcofluor staining. Similar to S. meliloti MucR, B. melitensis MucR also represses its own transcription and flagellar gene expression via the flagellar master regulator ftcR. More surprisingly, we demonstrate that MucR regulates a lipid A core modification in B. melitensis. These changes could account for the attenuated virulence of a mucR mutant. These data reinforce the idea that there is a common conserved circuitry between plant symbionts and animal pathogens that regulates the relationship they have with their hosts.
authors.affiliation: Unité de Recherche en Biologie Moléculaire (URBM), NARILIS, University of Namur (FUNDP), Namur, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Mirabella
authors.forename: M
authors.initials: M
authors.lastname: Terwagne
authors.forename: M S
authors.initials: MS
authors.lastname: Zygmunt
authors.forename: A
authors.initials: A
authors.lastname: Cloeckaert
authors.forename: X
authors.initials: X
authors.lastname: De Bolle
authors.forename: J J
authors.initials: JJ
authors.lastname: Letesson
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017347:Brucella melitensis / Q000235:genetics / Q000378:metabolism*; D002006:Brucellosis / Q000382:microbiology; D002462:Cell Membrane; D003902:Detergents / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D016962:Sinorhizobium meliloti / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D012333:RNA, Messenger; D012965:Sodium Chloride; D006861:Hydrogen Peroxide; D005964:Glucosyltransferases; C114346:cyclic beta(1-2) glucan synthetase, Brucella melitensis