Requirement for
            <i>Vibrio cholerae</i>
            Integration Host Factor in Conjugative DNA Transfer

McLeod, Sarah M.; Burrus, Vincent; Waldor, Matthew K.

doi:10.1128/jb.00564-06

Cited by 23 publications

(22 citation statements)

References 33 publications

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“…In the V. cholerae El Tor strain N16961, McLeod et al have found that, as in E. coli and Salmonella strains (2,33), over 100 genes are differentially regulated in an ihfA mutant (34). In the work presented here, we show that IHF positively influences the expression of virulence genes in the V. cholerae classical O395 strain.…”

Section: Discussionsupporting

confidence: 57%

Integration Host Factor Positively Regulates Virulence Gene Expression in Vibrio cholerae

et al. 2008

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Virulence gene expression in Vibrio cholerae is dependent upon a complex transcriptional cascade that is influenced by both specific and global regulators in response to environmental stimuli. Here, we report that the global regulator integration host factor (IHF) positively affects virulence gene expression in V. cholerae. Inactivation of ihfA and ihfB, the genes encoding the IHF subunits, decreased the expression levels of the two main virulence factors tcpA and ctx and prevented toxin-coregulated pilus and cholera toxin production. IHF was found to directly bind to and bend the tcpA promoter region at an IHF consensus site centered at position ؊162 by using gel mobility shift assays and DNase I footprinting experiments. Deletion or mutation of the tcpA IHF consensus site resulted in the loss of IHF binding and additionally disrupted the binding of the repressor H-NS. DNase I footprinting revealed that H-NS protection overlaps with both the IHF and the ToxT binding sites at the tcpA promoter. In addition, disruption of ihfA in an hns or toxT mutant background had no effect on tcpA expression. These results suggest that IHF may function at the tcpA promoter to alleviate H-NS repression.

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Section: Discussionsupporting

confidence: 57%

Integration Host Factor Positively Regulates Virulence Gene Expression in Vibrio cholerae

et al. 2008

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“…On one hand, ImmR was shown to bind diverse loci in the chromosome of B. subtilis, which could have a significant impact on host gene expression, and consequently on the fitness of the organism (78). On the other hand, several studies have reported the implication of host factors in the modulation of ICE dynamics, in both Grampositive and Gram-negative bacteria (48,90,91). At least three host factors are known to influence ICEBs1 mobility.…”

Section: Immr/imma As a Central Regulatory System Of Icebs1mentioning

confidence: 99%

“…Therefore, excision is not a rate-limiting step of SXT transfer. The host encoded nucleoid associated protein IHF (integration host factor), which is necessary for integration and excision of the bacteriophage λ in E. coli, is not required for SXT integration into or excision from the V. cholerae chromosome (48).…”

Section: Integration and Excisionmentioning

confidence: 99%

Biology of Three ICE Families: SXT/R391, ICE Bs1 , and ICE St1 /ICE St3

Carraro

Burrus

2014

Microbiol Spectr

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Integrative and Conjugative Elements (ICEs) are bacterial mobile genetic elements that play a key role in bacterial genomes dynamics and evolution. ICEs are widely distributed among virtually all bacterial genera. Recent extensive studies have unraveled their high diversity and complexity. The present review depicts the general conserved features of ICEs and describes more precisely three major families of ICEs that have been extensively studied in the past decade for their biology, their evolution and their impact on genomes dynamics. First, the large SXT/R391 family of ICEs disseminates antibiotic resistance genes and drives the exchange of mobilizable genomic islands (MGIs) between many enteric pathogens such as Vibrio cholerae. Second, ICEBs1 of Bacillus subtilis is the most well understood ICE of Gram-positive bacteria, notably regarding the regulation of its dissemination and its initially unforeseen extrachromosomal replication, which could be a common feature of ICEs of both Gram-positive and Gram-negative bacteria. Finally, ICESt1 and ICESt3 of Streptococcus thermophilus are the prototypes of a large family of ICEs widely distributed among various streptococci. These ICEs carry an original regulation module that associates regulators related to those of both SXT/R391 and ICEBs1. Study of ICESt1 and ICESt3 uncovered the cis-mobilization of related genomic islands (CIMEs) by a mechanism called accretion-mobilization, which likely represents a paradigm for the evolution of many ICEs and genomic islands. These three major families of ICEs give a glimpse about ICEs dynamics and their high impact on bacterial adaptation.

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“…This has been shown for SXT elements in Vibrio cholerae, which require the host factors IHF and Fis for excision, recombination, and conjugation (53). Host factors may be chromosomally encoded and not on the MGE itself, leading to the inability of the MGE to conjugate in their absence.…”

Section: Resultsmentioning

confidence: 99%

ICE Slu van, a 94-Kilobase Mosaic Integrative Conjugative Element Conferring Interspecies Transfer of VanB-Type Glycopeptide Resistance, a Novel Bacitracin Resistance Locus, and a Toxin-Antitoxin Stabilization System

et al. 2013

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A 94-kb integrative conjugative element (ICESluvan) transferable to Enterococcus faecium and Enterococcus faecalis from an animal isolate of Streptococcus lutetiensis consists of a mosaic of genetic fragments from different Gram-positive bacteria. A variant of ICESluvan was confirmed in S. lutetiensis from a patient. A complete Tn5382/Tn1549 with a vanB2 operon is integrated into a streptococcal ICESde3396-like region harboring a putative bacteriophage exclusion system, a putative agglutinin receptor precursor, and key components of a type IV secretion system. Moreover, ICESluvan encodes a putative MobC family mobilization protein and a relaxase and, thus, in total has all genetic components essential for conjugative transfer. A 9-kb element within Tn5382/Tn1549 encodes, among others, putative proteins similar to the TnpX site-specific recombinase in Faecalibacterium and VanZ in Paenibacillus, which may contribute to the detected low-level teicoplanin resistance. Furthermore, ICESluvan encodes a novel bacitracin resistance locus that is associated with reduced susceptibility to bacitracin when transferred to E. faecium. The expression of a streptococcal pezAT toxin-antitoxin-encoding operon of ICESluvan in S. lutetiensis, E. faecium, and E. faecalis was confirmed by reverse transcription (RT)-PCR, indicating an active toxin-antitoxin system which may contribute to stabilizing ICESluvan within new hosts. Junction PCR and DNA sequencing confirmed that ICESluvan excised to form a circular intermediate in S. lutetiensis, E. faecalis, and E. faecium. Transfer between E. faecalis cells was observed in the presence of helper plasmid pIP964. Sequence analysis of the original S. lutetiensis donor and enterococcal transconjugants showed that ICESluvan integrates in a site-specific manner into the C-terminal end of the chromosomal tRNA methyltransferase gene rumA.

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Requirement for Vibrio cholerae Integration Host Factor in Conjugative DNA Transfer

Cited by 23 publications

References 33 publications

Integration Host Factor Positively Regulates Virulence Gene Expression in Vibrio cholerae

Integration Host Factor Positively Regulates Virulence Gene Expression in Vibrio cholerae

Biology of Three ICE Families: SXT/R391, ICE Bs1 , and ICE St1 /ICE St3

ICE Slu van, a 94-Kilobase Mosaic Integrative Conjugative Element Conferring Interspecies Transfer of VanB-Type Glycopeptide Resistance, a Novel Bacitracin Resistance Locus, and a Toxin-Antitoxin Stabilization System

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