In vivo induced clpB1 gene of Vibrio cholerae is involved in different stress responses and affects in vivo cholera toxin production

Nag, Sanjay; Das, Soumita; Chaudhuri, Keya

doi:10.1016/j.bbrc.2005.04.052

Cited by 27 publications

(21 citation statements)

References 34 publications

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“…Gene expression in several bacterial pathogens, including Vibrio cholerae, Salmonella enterica, and Listeria monocytogenes (16,17), is regulated in response to salt concentration. In the present study, we tested whether H. pylori gene expression is altered in response to changes in salt concentration in the bacterial culture medium.…”

Section: Introductionmentioning

confidence: 99%

Regulation of Helicobacter pylori cagA Expression in Response to Salt

2007

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Section: Introductionmentioning

confidence: 99%

Regulation of Helicobacter pylori cagA Expression in Response to Salt

2007

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“…Given the wide distribution of T6SS gene clusters (7,8,(10)(11)(12)(13)(14)(15)(16)(17)(18) and the importance of the ACD domain in the host effector function of VgrG-1, we reasoned that other VgrG family members should exist that also contain extended C termini involved in T6SS effector function. The shortest of the V. cholerae VgrG proteins (VgrG-2) was used as a ''core'' VgrG to search the National Center for Biotechnology Information (NCBI) database for VgrG-like proteins (SI Fig.…”

Section: Functional Predictions For Vgrg Proteins Encoded By Other Gram-mentioning

confidence: 99%

“…Hcp genes are often found embedded in T6SS gene clusters and adjacent to vgrG genes (7,8,(10)(11)(12)(13)(14)(15)(16)(17)(18). The close proximity of hcp and vgrG genes to other T6SS genes, suggests that VgrG and Hcp may be preferred substrates or essential components of the T6SS apparatus.…”

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“…T6SS gene clusters are highly conserved and are present in one or more copies in many other pathogenic Gram-negative bacterial species, including Vibrio cholerae, Pseudomonas aeruginosa, Yersinia pestis, Escherichia coli, Salmonella enterica, Agrobacterium tumefaciens, Rhizobium leguminosarum, Francisella tularensis, Burkholderia mallei, and Edwardsiella species (8,(10)(11)(12)(13)(14)(15)(16)(17)(18). T6SS genes have been implicated in virulence-related processes in several of these organisms (14,(18)(19)(20)(21)(22)(23).…”

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confidence: 99%

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Type VI secretion system translocates a phage tail spike-like protein into target cells where it cross-links actin

Pukatzki

Revel

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

663

879

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Genes encoding type VI secretion systems (T6SS) are widely distributed in pathogenic Gram-negative bacterial species. In Vibrio cholerae, T6SS have been found to secrete three related proteins extracellularly, VgrG-1, VgrG-2, and VgrG-3. VgrG-1 can covalently cross-link actin in vitro, and this activity was used to demonstrate that V. cholerae can translocate VgrG-1 into macrophages by a T6SS-dependent mechanism. Protein structure search algorithms predict that VgrG-related proteins likely assemble into a trimeric complex that is analogous to that formed by the two trimeric proteins gp27 and gp5 that make up the baseplate ''tail spike'' of Escherichia coli bacteriophage T4. VgrG-1 was shown to interact with itself, VgrG-2, and VgrG-3, suggesting that such a complex does form. Because the phage tail spike protein complex acts as a membrane-penetrating structure as well as a conduit for the passage of DNA into phage-infected cells, we propose that the VgrG components of the T6SS apparatus may assemble a ''cellpuncturing device'' analogous to phage tail spikes to deliver effector protein domains through membranes of target host cells.bacteriophage ͉ cytotoxicity ͉ Vibrio cholerae ͉ virulence

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“…The mutated gene(s) in such mutants remains unverified. It has been shown that pigment production in V. cholerae can be induced in response to stress, particularly hyperosmotic shock and elevated temperatures (1,3,5,22). The pigment formation is initiated in late-exponential to postexponential growth of the bacteria (1,5).…”

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Role of Melanin Pigment in Expression of Vibrio cholerae Virulence Factors

et al. 2009

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We identified the mutated gene locus in a pigment-overproducing Vibrio cholerae mutant of strain A1552. The deduced gene product is suggested to be an oxidoreductase based on partial homology to putative homogentisate 1,2-dioxygenase in Pseudomonas aeruginosa and Mesorhizobium loti, and we propose that the gene VC1345 in the V. cholerae genome be denoted hmgA in accordance with the nomenclature for other species. The hmgA::mini-Tn5 mutant showed a nonpigmented phenotype after complementation with a plasmid clone carrying the WT hmgA ؉ locus. Microarray transcription analysis revealed that expression of hmgA and the neighboring genes encoding a postulated two-component sensor system was growth phase dependent. Results from quantitative reverse transcription-PCR analysis showed that hmgA operon expression was reduced in the rpoS mutant, but pigment production by the WT V. cholerae or the hmgA mutant was not detectably influenced by the stationary-phase regulator RpoS. The pigmented mutant showed increased UV resistance in comparison with the WT strain. Interestingly, the pigment-producing mutant expressed more toxin-coregulated pilus and cholera toxin than WT V. cholerae. Moreover, the hmgA mutant showed a fivefold increase in the ability to colonize the intestines of infant mice. A possible mechanism by which pigment production might cause induction of the ToxR regulon due to generation of hydrogen peroxide was supported by results from tests showing that externally supplied H 2 O 2 led to higher TcpA levels. Taken together, our findings suggest that melanin pigment formation may play a role in V. cholerae virulence factor expression.

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In vivo induced clpB1 gene of Vibrio cholerae is involved in different stress responses and affects in vivo cholera toxin production

Cited by 27 publications

References 34 publications

Regulation of Helicobacter pylori cagA Expression in Response to Salt

Regulation of Helicobacter pylori cagA Expression in Response to Salt

Type VI secretion system translocates a phage tail spike-like protein into target cells where it cross-links actin

Role of Melanin Pigment in Expression of Vibrio cholerae Virulence Factors

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