The Gene Encoding the 17-kDa Antigen of<i>Bartonella henselae</i>is Located within a Cluster of Genes Homologous to the<i>virB</i>Virulence Operon

Padmalayam, Indira; Karem, Kevin L.; Massung, Robert F.; Baumstark, Barbara R.

doi:10.1089/10445490050043344

Cited by 53 publications

(47 citation statements)

References 22 publications

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“…Genetic comparison of this locus revealed that the 17kDa protein it encoded was a VirB5 homolog and further exploration of the locus revealed the presence of homologs of other members of the T4SS upstream and downstream of VirB5 [44,45]. The putative promoter region of the operon was also identified and its expression was shown to be induced when B. henselae was cultivated with human microvascular endothelial cells [46].…”

Section: Step 1: Infection Prior To Bacteraemiamentioning

confidence: 99%

Strategies of exploitation of mammalian reservoirs by Bartonella species

Deng

Rhun

Buffet

et al. 2012

Vet Res

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Numerous mammal species, including domestic and wild animals such as ruminants, dogs, cats and rodents, as well as humans, serve as reservoir hosts for various Bartonella species. Some of those species that exploit non-human mammals as reservoir hosts have zoonotic potential. Our understanding of interactions between bartonellae and reservoir hosts has been greatly improved by the development of animal models for infection and the use of molecular tools allowing large scale mutagenesis of Bartonella species. By reviewing and combining the results of these and other approaches we can obtain a comprehensive insight into the molecular interactions that underlie the exploitation of reservoir hosts by Bartonella species, particularly the well-studied interactions with vascular endothelial cells and erythrocytes.

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Section: Step 1: Infection Prior To Bacteraemiamentioning

confidence: 99%

Strategies of exploitation of mammalian reservoirs by Bartonella species

Deng

Rhun

Buffet

et al. 2012

Vet Res

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“…They bear Walker A (motif I) and B (motif II or DExx box) NTP-binding sequences [88] and may use the energy of Rhizobium etli bacterium; N2-fixation [154] Sinorhizobium meliloti bacterium; N2-fixation [14,15,17] Shigella flexneri plasmid ColIb P9 bacterium; diarrhoea / dysentery [155] Bartonella henselae and tribocorum bacterium; cat scratch disease, bacteremia [156][157][158][159][160] Campylobacter jejuni bacterium; bacterial diarrhoea [161,162] Toxoplasma gondii protozoon; toxoplasmosis (encephalitis) [54] Leishmania donovani protozoon; leishmaniasis [54] Mycobacterium tuberculosis bacterium; tuberculosis [54] Bordetella bronchiseptica bacterium; bronchitis [14,15,17] Enterobacter aerogenes bacterium; nosocomial infections [11] Actinobacillus actinomycetemcomitans bacterium; periodontitis [14,15,17,163,164] Escherichia coli bacterium; diarrhea [11] Caulobacter crescentus bacterium; non-pathogenic [14,15,17] Coxiella burnetii bacterium; acute febrile disease, endocarditis, pneumonitis [165,166] Thiobacillus ferroxidans bacterium; iron oxidation [14,15,17] Wolbachia intracellular symbiont of arthropods; sexual alterations in host [167,168] Ralstonia eutrophantus bacterium; heavy-metal resistance [11,169] Salmonella typhi, typhimurium and enteriditis bacterium; typhus, salmonellosis …”

Section: Transfer Factors In Conjugative Type-iv Secretionmentioning

confidence: 99%

Coupling Factors in Macromolecular Type-IV Secretion Machineries

Gomis‐Rüth

Sola

Cruz³

et al. 2004

CPD

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Type IV secretion systems (T4SSs) are bacterial multiprotein organelles specialised in the transfer of (nucleo)protein complexes across cell membranes. They are essential for conjugation, bacterial-induced tumour formation in plant cells, as observed in Agrobacterium, toxin secretion, like in Bordetella and Helicobacter, cell-to-cell translocation of virulence factors, and intracellular activity of mammalian pathogens like Legionella. By enabling conjugative DNA delivery, these systems contribute to the spread of antibiotic resistance genes among bacteria. These translocons are made up by 10-15 proteins that are analogous to Vir proteins of Agrobacterium and traverse both membranes and the periplasmic space in between in Gram-negative bacteria. Their secretion substrates range from single-stranded DNA / protein complexes to multicomponent toxins and they are assisted by integral inner-membrane coupling factors, the multimeric type-IV coupling proteins (T4CPs), to connect the macromolecular complexes to be transferred with the secretory conduit. To do so, these T4CPs may be required to localise close to the secretion machinery within the donor cell. The T4CP structural prototype is the hexameric protein TrwB of Escherichia coli conjugative plasmid R388, closely related to Agrobacterium VirD4 protein. It is responsible for coupling the relaxosome with the DNA transport apparatus during cell mating. T4CP family members are related to SpoIIIE/FtsK proteins, essential for DNA pumping during sporulation and cell division. These features suggest possible mechanisms for conjugal T4CP function: as a simple coupler between two molecular machines, as a rotating device to pump DNA through the type-IV transport pore, or as a DNA injector, whereby its central channel would function as part of the transport pore.

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“…The pathogens utilizing type IV systems during infection include Helicobacter pylori (12), Bordetella pertussis (3), Brucella spp. (31, 42), Bartonella henselae (35,40), and Legionella pneumophila (47). A type IV system of H. pylori exports CagA to the cytosol of mammalian cells (32,41,44), whereas a related system exports pertussis toxin across the outer membrane of B. pertussis (3).…”

mentioning

confidence: 99%

Activities of virE1 and the VirE1 Secretion Chaperone in Export of the Multifunctional VirE2 Effector via an Agrobacterium Type IV Secretion Pathway

et al. 2001

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Agrobacterium tumefaciens uses a type IV secretion system to deliver oncogenic nucleoprotein particles and effector proteins, such as the multifunctional VirE2 protein, to plant cells. In this study, we examined the function of virE1 and its product, the VirE1 secretion chaperone, in mediating VirE2 export. A nonpolar virE1 null mutant accumulated low levels of VirE2, and trans expression of virE1 in this mutant only partially restored VirE2 abundance. Deletion of virE1 did not affect transcription but decreased translation of virE2, as shown by analysis of lacZ transcriptional and translational fusions. VirE2 was stable for a prolonged period, more than 6 h, when it was expressed in cis with virE1, and it exhibited half-lives of about 2 h when it was expressed in trans with virE1 and less than 10 min when it was expressed in the absence of virE1, as shown by pulse-chase experiments. VirE1 stabilized VirE2 via an interaction with a domain near the N terminus of VirE2, as shown by analyses of VirE2 truncation and insertion mutants synthesized in A. tumefaciens. VirE1 self-association was demonstrated by using bacteriophage cI repressor fusion and pull-down assays, and evidence of VirE1 homomultimerization in vivo was obtained by native polyacrylamide gel electrophoresis and gel filtration chromatography. A putative VirE1-VirE2 complex with a molecular mass of about 70 to 80 kDa was detected by gel filtration chromatography of extracts from wild-type cells, whereas higher-order VirE2 complexes or aggregates were detected in extracts from a virE1 mutant. Taken together, our findings show that virE1 contributes in several ways to VirE2 export:(i) virE1 regulates efficient virE2 translation in the context of expression from the native P virE promoter; (ii) the VirE1 secretion chaperone stabilizes VirE2, most probably via an interaction with an N-terminal domain; and (iii) VirE1 forms a VirE1-VirE2 complex with a predicted 2:1 stoichiometry that inhibits assembly of higher-order VirE2 complexes or aggregates.Agrobacterium tumefaciens transfers at least three macromolecular substrates, oncogenic T-DNA, VirE2 single-stranded DNA-binding protein (SSB), and VirF protein, to plant cells during the course of infection (8). Substrate transfer is mediated by a type IV secretion system assembled from the products of the ϳ9.5-kbp virB operon and the virD4 gene (29). This transfer system is a bona fide conjugation apparatus, as suggested by its ancestral relatedness to transfer systems (Tra) of several broad-host-range plasmids and as demonstrated by its ability to transfer the mobilizable IncQ plasmid RSF1010 to bacterial and plant recipient cells. In recent years, other type IV systems have been shown to contribute to the virulence of several mammalian pathogens. The pathogens utilizing type IV systems during infection include Helicobacter pylori (12), Bordetella pertussis (3), Brucella spp. (31, 42), Bartonella henselae (35,40), and Legionella pneumophila (47). A type IV system of H. pylori exports CagA to the cytosol of mamm...

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The Gene Encoding the 17-kDa Antigen ofBartonella henselaeis Located within a Cluster of Genes Homologous to thevirBVirulence Operon

Cited by 53 publications

References 22 publications

Strategies of exploitation of mammalian reservoirs by Bartonella species

Strategies of exploitation of mammalian reservoirs by Bartonella species

Coupling Factors in Macromolecular Type-IV Secretion Machineries

Activities of virE1 and the VirE1 Secretion Chaperone in Export of the Multifunctional VirE2 Effector via an Agrobacterium Type IV Secretion Pathway

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