Filamentous vibriophage fs2 encoding the<i>rst</i>C gene integrates into the same chromosomal region as cholera toxin X

Nguyen, Doan; Nguyen, Binh Minh; Tran, Huy Hoang; Ngo, Tuan Cuong; Le, Thanh Huong; Nguyen, Hoai Thu; Albert, M. John; Iwami, Mamoru; Ehara, Masahiko

doi:10.1111/j.1574-6968.2008.01200.x

Cited by 11 publications

(8 citation statements)

References 8 publications

(13 reference statements)

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“…Most strains isolated in India in 1993 had two copies of the ctx gene in tandem connected by two RSs [28]. Previously we reported the integration sites of vibriophage fs2 in a classical strain and in a strain of V. cholerae O139 [29]. It is noteworthy to examine whether two filamentous phages, fs1 and fs2 integrate into the chromosome of epidemic strains of V. cholerae O1 at the same time as shown in this study and the previous study [29] flanking the CTX phage.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Vibrio cholerae O139 of an Aquatic Isolate in Northern Vietnam

Nguyen

Ngo²,

Tran³

et al. 2012

TOMICROJ

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During the cholera survey in Namdinh province (northern Vietnam) in July, 2010, one strain of Vibrio cholerae O139 was isolated from 7 environmental water samples positive for ctxA, toxR, VCO139 genes and named as V. cholerae O139, ND1 strain. This strain was lysogenic harbouring a genome similar to the filamentous phage fs1. The replicative form DNA of this phage (named as ND1-fs1, 6856 bp) was sequenced and compared with the other filamentous phages. The filamentous phage ND1-fs1 integrates into the region between ctxB and rtxA genes. The genetic organization of the CTXϕ of V. cholerae O139, strain ND1 was determined and the schematic representation of the genetic organization was shown together with the ND1-fs1 prophage.

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Section: Resultsmentioning

confidence: 99%

Characterization of Vibrio cholerae O139 of an Aquatic Isolate in Northern Vietnam

Nguyen

Ngo²,

Tran³

et al. 2012

TOMICROJ

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“…In this region, fs2 carries the rstC gene and a large non-coding sequence. The rstC gene is the most notable feature of the fs2 genome and confers important biological function to this phage, namely the capacities to horizontally transfer the rstC gene and to affect the assembly of fimbriae in vivo [14]. The large non-coding sequence contains stem-loop structures and is suspected to correspond to the intergenic (IG) region of coliphages [21].…”

Section: Discussionmentioning

confidence: 99%

“…Phage 493 is conjectured to have played some role in the emergence of the O139 epidemic serotype of V. cholerae [5]. Phage fs2 can horizontally transfer its rstC gene to the classical strain and influence the assembly of fimbriae in an animal model [14]. Almost all of these phages have been proven to be integrated into the host chromosome [6], [9], [15], [16].…”

Section: Introductionmentioning

confidence: 99%

Isolation and Characterization of the New Mosaic Filamentous Phage VFJ Φ of Vibrio cholerae

2013

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Filamentous phages have distinguished roles in conferring many pathogenicity and survival related features to Gram-negative bacteria including the medically important Vibrio cholerae, which carries factors such as cholera toxin on phages. A novel filamentous phage, designated VFJΦ, was isolated in this study from an ampicillin and kanamycin-resistant O139 serogroup V. cholerae strain ICDC-4470. The genome of VFJΦ is 8555 nucleotides long, including 12 predicted open reading frames (ORFs), which are organized in a modular structure. VFJΦ was found to be a mosaic of two groups of V. cholerae phages. A large part of the genome is highly similar to that of the fs2 phage, and the remaining 700 bp is homologous to VEJ and VCYΦ. This 700 bp region gave VFJΦ several characteristics that are not found in fs2 and other filamentous phages. In its native host ICDC-4470 and newly-infected strain N16961, VFJΦ was found to exist as a plasmid but did not integrate into the host chromosome. It showed a relatively wide host range but did not infect the classical biotype O1 V. cholerae strains. After infection, the host strains exhibited obvious inhibition of both growth and flagellum formation and had acquired a low level of ampicillin resistance and a high level of kanamycin resistance. The antibiotic resistances were not directly conferred to the hosts by phage-encoded genes and were not related to penicillinase. The discovery of VFJΦ updates our understanding of filamentous phages as well as the evolution and classification of V. cholerae filamentous phage, and the study provides new information on the interaction between phages and their host bacteria.

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“…The results described here provide new insights into the role of the RS1 satellite phage in V. cholerae evolution, and presumably that of other bacteria which carry phages with similar antirepressors involved in lysogeny (32,33). Understanding the CTX genetic switch may lead to comprehension of possible thematic insights about lysogenic phages which show a reversible pattern of induction and reestablishment of lysogeny.…”

Section: Discussionmentioning

confidence: 96%

“…Colony blots or Southern blots were prepared using nylon membranes (Hybond; Amersham Biosciences, Uppsala, Sweden). The blots were hybridized with radioactively labeled probes ([␣- 32 P]dCTP at 3,000 Ci/mmol; PerkinElmer, Boston, MA) and autoradiographed by standard methods (20).…”

Section: Methodsmentioning

confidence: 99%

RS1 Satellite Phage Promotes Diversity of Toxigenic Vibrio cholerae by Driving CTX Prophage Loss and Elimination of Lysogenic Immunity

et al. 2014

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bIn El Tor biotype strains of toxigenic Vibrio cholerae, the CTX prophage often resides adjacent to a chromosomally integrated satellite phage genome, RS1, which produces RS1 particles by using CTX prophage-encoded morphogenesis proteins. RS1 encodes RstC, an antirepressor against the CTX repressor RstR, which cooperates with the host-encoded LexA protein to maintain CTX lysogeny. We found that superinfection of toxigenic El Tor strains with RS1, followed by inoculation of the transductants into the adult rabbit intestine, caused elimination of the resident CTX prophage-producing nontoxigenic derivatives at a high frequency. Further studies using recA deletion mutants and a cloned rstC gene showed that the excision event was recA dependent and that introduction of additional copies of the cloned rstC gene instead of infection with RS1 was sufficient to enhance CTX elimination. Our data suggest that once it is excised from the chromosome, the elimination of CTX prophage from host cells is driven by the inability to reestablish CTX lysogeny while RstC is overexpressed. However, with eventual loss of the additional copies of rstC, the nontoxigenic derivatives can act as precursors of new toxigenic strains by acquiring the CTX prophage either through reinfection with CTX or by chitin-induced transformation. These results provide new insights into the role of RS1 in V. cholerae evolution and the emergence of highly pathogenic clones, such as the variant strains associated with recent devastating epidemics of cholera in Asia, sub-Saharan Africa, and Haiti.

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Filamentous vibriophage fs2 encoding therstC gene integrates into the same chromosomal region as cholera toxin X

Cited by 11 publications

References 8 publications

Characterization of Vibrio cholerae O139 of an Aquatic Isolate in Northern Vietnam

Characterization of Vibrio cholerae O139 of an Aquatic Isolate in Northern Vietnam

Isolation and Characterization of the New Mosaic Filamentous Phage VFJ Φ of Vibrio cholerae

RS1 Satellite Phage Promotes Diversity of Toxigenic Vibrio cholerae by Driving CTX Prophage Loss and Elimination of Lysogenic Immunity

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