Repression of bacterial motility by a novel fimbrial gene product.
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.
Li
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Department of Microbiology and Immunology, University of Maryland School of Medicine and Veterans Affairs Medical Center, Baltimore, MA 21201, USA.
Rasko
D A
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Lockatell
C V
CV
Johnson
D E
DE
Mobley
H L
HL
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
D001426:Bacterial Proteins; C436707:MrpJ protein, Proteus mirabilis; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D005408:Flagellin; C067138:flaA protein, bacteria