RICHARD, Egill; DARRACQ, Baptiste; LITTNER, Eloi; VIT, Claire; WHITEWAY, Clémence; BOS, Julia; FOURNES, Florian; GARRISS, Geneviève; CONTE, Valentin; LAPAILLERIE, Delphine; PARISSI, Vincent; ROUSSET, François; SKOVGAARD, Ole; BIKARD, David; ROCHA, Eduardo; MAZEL, Didier; LOOT, Céline

doi:10.1101/2022.08.03.502626

Langue

Document de travail - Pré-publication

Résumé en anglais

The integron is a bacterial recombination system that allows acquisition, stockpiling and expression of promoterless genes embedded in cassettes. Some integrons, like the one found in the second chromosome of Vibrio cholerae, can be particularly massive and contain hundreds of non-expressed cassettes. It is unclear how such genetic structures can be stabilized in bacterial genomes. Here, we reveal that the orientation of integrons toward replication within bacterial chromosomes is essential to their stability. Indeed, we show that upon inversion of the V. cholerae chromosomal integron, its plasticity is dramatically increased. This correlates with a strong growth defect which we show is mostly due to the excision of a particular type of cassettes bearing their own promoter and encoding toxin-antitoxin systems. This so called "abortive excision" of toxin-antitoxin systems can prevent the inversion of chromosomal integrons and the associated extensive loss of cassettes. Our analysis of the available sedentary chromosomal integrons in genome database show a robust correlation between the size of the cassette array and the number of toxin-antitoxin cassettes. This study thus provides a striking example of the relationship between genome organization, genome stability, and an emerging property of toxin-antitoxin systems.< Réduire

Mots clés en anglais

bacterial evolution and plasticity

genome organization

genetic stability

sitespecific recombination

mobile elements

sedentary chromosomal integron

toxin-antitoxin cassettes

URI

https://oskar-bordeaux.fr/handle/20.500.12278/182190

DOI

http://dx.doi.org/10.1101/2022.08.03.502626

Project ANR

Etude de l'impact des intégrons chromosiques sur l'évolution des bactéries
Integrative Biology of Emerging Infectious Diseases

Unités de recherche

MFP (Laboratoire Microbiologie Fondamentale et Pathogénicité) - UMR 5234

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Genetic drivers of chromosomal integron stability

Langue

Résumé en anglais

Mots clés en anglais

URI

DOI

Project ANR

Unités de recherche