title: Repression of bacterial motility by a novel fimbrial gene product.
abstract: Proteus mirabilis is a common uropathogen in patients with long-term catheterization or with structural or functional abnormalities in the urinary tract. The mannose-resistant, Proteus-like (MR/P) fimbriae and flagellum are among virulence factors of P.mirabilis that contribute to its colonization in a murine model of ascending urinary tract infection. mrpJ, the last of nine genes of the mrp operon, encodes a 107 amino acid protein that contains a putative helix-turn-helix domain. Using transcriptional lacZ fusions integrated into the chromosome and mutagenesis studies, we demonstrate that MrpJ represses transcription of the flagellar regulon and thus reduces flagella synthesis when MR/P fimbriae are produced. The repression of flagella synthesis by MrpJ is confirmed by electron microscopy. However, a gel mobility shift assay indicates that MrpJ does not bind directly to the regulatory region of the flhDC operon. The isogenic mrpJ null mutant of wild-type P.mirabilis strain HI4320 is attenuated in the murine model. Our data also indicate that PapX encoded by a pap (pyelonephritis- associated pilus) operon of uropathogenic Escherichia coli is a functional homolog of MrpJ.
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine and Veterans Affairs Medical Center, Baltimore, MA 21201, USA.
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.forename: D A
authors.initials: DA
authors.lastname: Rasko
authors.forename: C V
authors.initials: CV
authors.lastname: Lockatell
authors.forename: D E
authors.initials: DE
authors.lastname: Johnson
authors.forename: H L
authors.initials: HL
authors.lastname: Mobley
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D010861:Fimbriae, Bacterial / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure; D005407:Flagella / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D005408:Flagellin / Q000235:genetics*; D018257:Helix-Loop-Helix Motifs; D007700:Kinetics; D051379:Mice; D008808:Mice, Inbred CBA; D008854:Microscopy, Electron; D009068:Movement / Q000502:physiology; D016296:Mutagenesis; D016254:Mutagenesis, Insertional; D009876:Operon; D011512:Proteus Infections / Q000382:microbiology; D011513:Proteus mirabilis / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion; D013489:Suppression, Genetic; D014158:Transcription, Genetic; D014552:Urinary Tract Infections / Q000382:microbiology; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C436707:MrpJ protein, Proteus mirabilis; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D005408:Flagellin; C067138:flaA protein, bacteria