CTXφ: Exploring new alternatives in host factor-mediated filamentous phage replications

Martínez, Eriel; Campos-Gómez, Javier; Barre, François‐Xavier

doi:10.1080/21597081.2015.1128512

Cited by 6 publications

(7 citation statements)

References 21 publications

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“…The free 3′ end can now serve as a primer for the host DNA polymerase holoenzyme to synthesize a new + strand, displacing the original + strand as it progresses. In Ff, these pII‐mediated steps are also dependent on the host replicative Rep helicase and integration host factor, whereas some Vibrio and Pseudomonas Pf phages use the hosts alternate DNA repair helicase UvrD and the histone‐like HU proteins . Once the replication completes a full circle, pII cleaves and cyclizes the free ends resulting in a ssDNA IF and dsDNA RF .…”

Section: Filamentous Phage Life Cycle: Genome Replicationmentioning

confidence: 99%

Filamentous phages: masters of a microbial sharing economy

2019

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Bacteriophage (“bacteria eaters”) or phage is the collective term for viruses that infect bacteria. While most phages are pathogens that kill their bacterial hosts, the filamentous phages of the sub‐class Inoviridae live in cooperative relationships with their bacterial hosts, akin to the principal behaviours found in the modern‐day sharing economy: peer‐to‐peer support, to offset any burden. Filamentous phages impose very little burden on bacteria and offset this by providing service to help build better biofilms, or provision of toxins and other factors that increase virulence, or modified behaviours that provide novel motile activity to their bacterial hosts. Past, present and future biotechnology applications have been built on this phage–host cooperativity, including DNA sequencing technology, tools for genetic engineering and molecular analysis of gene expression and protein production, and phage‐display technologies for screening protein–ligand and protein–protein interactions. With the explosion of genome and metagenome sequencing surveys around the world, we are coming to realize that our knowledge of filamentous phage diversity remains at a tip‐of‐the‐iceberg stage, promising that new biology and biotechnology are soon to come.

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Section: Filamentous Phage Life Cycle: Genome Replicationmentioning

confidence: 99%

Filamentous phages: masters of a microbial sharing economy

2019

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“…In particular, cycles of excision and reintegration of CTXΦ promote the continuous apparition of clones producing new potentially more active forms of cholera toxin, which is a major clinical concern. The presence of an integrated copy of CTXΦ limits the possibilities for integration of new phage variants because it limits rolling-circle amplification of CTXΦ phages from the same incompatibility group (36–39). Thus, excision of previously integrated CTX copies is crucial for the spreading of new toxin variants.…”

Section: Discussionmentioning

confidence: 99%

“…The HJs are converted into product by replication. CTXΦ integration is facilitated by rolling-circle replication, which amplifies the number of copies of its genome, and by a ubiquitous base excision repair enzyme, Endo III, which stabilizes HJs (36–38). In contrast, TLCΦ integration depends on the addition of a full cross-over between its attachment site and dif1 by a yet poorly understood FtsK-independent Xer recombination reaction (15).…”

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confidence: 99%

The TLCΦ satellite phage harbors a Xer recombination activation factor

Midonet

Miele

Paly

et al. 2019

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

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The circular chromosomes of bacteria can be concatenated into dimers by homologous recombination. Dimers are solved by the addition of a cross-over at a specific chromosomal site,dif, by 2 related tyrosine recombinases, XerC and XerD. Each enzyme catalyzes the exchange of a specific pair of strands. Some plasmids exploit the Xer machinery for concatemer resolution. Other mobile elements exploit it to integrate into the genome of their host. Chromosome dimer resolution is initiated by XerD. The reaction is under the control of a cell-division protein, FtsK, which activates XerD by a direct contact. Most mobile elements exploit FtsK-independent Xer recombination reactions initiated by XerC. The only notable exception is the toxin-linked cryptic satellite phage ofVibrio cholerae, TLCΦ, which integrates into and excises from thedifsite of the primary chromosome of its host by a reaction initiated by XerD. However, the reaction remains independent of FtsK. Here, we show that TLCΦ carries a Xer recombination activation factor, XafT. We demonstrate in vitro that XafT activates XerD catalysis. Correspondingly, we found that XafT specifically interacts with XerD. We further show that integrative mobile elements exploiting Xer (IMEXs) encoding a XafT-like protein are widespread in gamma- and beta-proteobacteria, including human, animal, and plant pathogens.

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“…Genome. Cross-talk between GIs and prophages in V. cholerae is a well-known phenomenon (29,30). However, the influence of acquired functions in the functionality of genes present in the core genome is not known.…”

Section: Cross-talk Between Horizontally Acquired Genetic Elements and Corementioning

confidence: 99%

“…Core Genome-Encoded RecA Helps CTXΦ to Overcome Host Immunity and Reinfect V. cholerae. Other than phage-encoded RstA, chromosomally encoded UvrD helicase and LexA also play an important role in CTXΦ replication (30). It was reported that RstR, the CTXΦ encoded transcriptional factor, binds to the rstA promoter (P rstA ) and represses its expression from the prophage genome (31).…”

Section: Cross-talk Between Horizontally Acquired Genetic Elements and Corementioning

confidence: 99%

Molecular insights into the genome dynamics and interactions between core and acquired genomes of Vibrio cholerae

Pant

Bag

Saha

et al. 2020

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

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Bacterial species are hosts to horizontally acquired mobile genetic elements (MGEs), which encode virulence, toxin, antimicrobial resistance, and other metabolic functions. The bipartite genome of Vibrio cholerae harbors sporadic and conserved MGEs that contribute in the disease development and survival of the pathogens. For a comprehensive understanding of dynamics of MGEs in the bacterial genome, we engineered the genome of V. cholerae and examined in vitro and in vivo stability of genomic islands (GIs), integrative conjugative elements (ICEs), and prophages. Recombinant vectors carrying the integration module of these GIs, ICE and CTXΦ, helped us to understand the efficiency of integrations of MGEs in the V. cholerae chromosome. We have deleted more than 250 acquired genes from 6 different loci in the V. cholerae chromosome and showed contribution of CTX prophage in the essentiality of SOS response master regulator LexA, which is otherwise not essential for viability in other bacteria, including Escherichia coli. In addition, we observed that the core genome-encoded RecA helps CTXΦ to bypass V. cholerae immunity and allow it to replicate in the host bacterium in the presence of similar prophage in the chromosome. Finally, our proteomics analysis reveals the importance of MGEs in modulating the levels of cellular proteome. This study engineered the genome of V. cholerae to remove all of the GIs, ICEs, and prophages and revealed important interactions between core and acquired genomes.

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CTXφ: Exploring new alternatives in host factor-mediated filamentous phage replications

Cited by 6 publications

References 21 publications

Filamentous phages: masters of a microbial sharing economy

Filamentous phages: masters of a microbial sharing economy

The TLCΦ satellite phage harbors a Xer recombination activation factor

Molecular insights into the genome dynamics and interactions between core and acquired genomes of Vibrio cholerae

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