title: Brucella melitensis cyclic di-GMP phosphodiesterase BpdA controls expression of flagellar genes.
abstract: Brucella melitensis encounters a variety of conditions and stimuli during its life cycle--including environmental growth, intracellular infection, and extracellular dissemination--which necessitates flexibility of bacterial signaling to promote virulence. Cyclic-di-GMP is a bacterial secondary signaling molecule that plays an important role in adaptation to changing environments and altering virulence in a number of bacteria. To investigate the role of cyclic-di-GMP in B. melitensis, all 11 predicted cyclic-di-GMP-metabolizing proteins were separately deleted and the effect on virulence was determined. Three of these cyclic-di-GMP-metabolizing proteins were found to alter virulence. Deletion of the bpdA and bpdB genes resulted in attenuation of virulence of the bacterium, while deletion of the cgsB gene produced a hypervirulent strain. In a Vibrio reporter system to monitor apparent alteration in levels of cyclic-di-GMP, both BpdA and BpdB displayed a phenotype consistent with cyclic-di-GMP-specific phosphodiesterases, while CgsB displayed a cyclic-di-GMP synthase phenotype. Further analysis found that deletion of bpdA resulted in a dramatic decrease in flagellar promoter activities, and a flagellar mutant showed similar phenotypes to the bpdA and bpdB mutant strains in mouse models of infection. These data indicate a potential role for regulation of flagella in Brucella melitensis via cyclic-di-GMP.
authors.affiliation: Department of Pathobiological Sciences, University of Wisconsin—Madison, 1656 Linden Dr, Madison,Wisconsin 53706, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Petersen
authors.forename: Pallab
authors.initials: P
authors.lastname: Chaudhuri
authors.forename: Chris
authors.initials: C
authors.lastname: Gourley
authors.forename: Jerome
authors.initials: J
authors.lastname: Harms
authors.forename: Gary
authors.initials: G
authors.lastname: Splitter
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017347:Brucella melitensis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D002006:Brucellosis / Q000382:microbiology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D005407:Flagella / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D011401:Promoter Regions, Genetic; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; C062025:bis(3',5')-cyclic diguanylic acid; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D006152:Cyclic GMP