Xavier De Bolle

Brucella cell cycle and infection

Dissecting the molecular mechanisms that govern Brucella abortus cell cycle during infection

Prof. Xavier De Bolle PhD

UNamur, Department of biology, Research Unit in Biology of Microorganisms (URBM)

Member of the Namur Research Pole in Infectiology (NaRePI)

Research portal UNamur  |  ORCID  |  ResearchGatewww.urbm.be/research-groups/xavier-de-bolle

Expertise and research interests

Prof. Xavier De Bolle is an expert in the field of molecular bacteriology, with a special focus on Brucella abortus. His research group studies basic molecular biology of the Brucella abortus, a bacterial pathogen responsible for brucellosis, which cause abortion in domestic animals and undulant fever in humans. The group discovered that B. abortus is asymmetrically organized at the molecular level, and tries to evaluate the importance of this asymmetry in simplified models of infection. They also set up molecular tools, which makes it possible to follow cell cycle progression of B. abortus in culture and inside host cells. They discovered that a large fraction of the bacteria block their DNA replication during the first hours of a cellular infection. Their current research topics mainly include the biogenesis and homeostasis of the enveloppe and envelope-associated structures during polar growth and infection.

They use genetic approaches such as deletion strain generation and characterization, genome-wide transposon mutagenesis followed by deep sequencing (Tn-seq), protein binding site identification on B. abortus chromosomes (ChIP-seq) and generation of genetically engineered strains to follow protein localization in B. abortus.

Group members

Postdoc researcher: Dr. Katy Poncin

PhD students: Jonathan De Stercke, Charline Focant, Adélie Lanoy, Thomas Rouma and Audrey Verhaeghe

Research projects

  • ONGOING Characterization of LD-transpeptidases in the intracellular pathogen Brucella abortus. Ongoing PhD thesis by Jonathan De Stercke.
  • ONGOING Envelope biosynthesis during growth and cell division of Brucella abortus. Ongoing PhD thesis by Audrey Verhaeghe.
  • ONGOING PAChiDERM: YDPase ACtivities In diDERM bacteria (https://arc-pachiderm.weebly.com/). Supported by an ARC grant. It gathers three professors from UCLouvain (Jean-François Collet, Géraldine Laloux, Patrice Soumillion) and one from UNamur (Xavier De Bolle) within a highly interdisciplinary team.

  • ONGOING Study of Polymyxin B resistance in naturally resistant Brucella abortus and Sphingobium yanoikuyae. Postdoctoral research by Dr. Katy Poncin.
  • ONGOING Study of the biogenesis of the VirB type IV secretion system in Brucella abortus. Ongoing PhD thesis by Charline Focant.
  • ONGOING Envelope stress response in Brucella abortus. Ongoing PhD thesis by Adélie Lanoy.
  • ONGOING Characterization of the protective immune response against pulmonary infection by Acinetobacter baumannii in mice. Ongoing PhD thesis by Thomas Rouma. Under co-supervision by Prof. Eric Muraille, ULB (promoter) and Prof. Xavier De Bolle, UNamur (promoter).
  • Involvement of cyclic-diGMP on Brucella abortus cell morphology and infection. Postdoctoral research by Angéline Reboul (Oct 2017 - 2022).

Selected publications

Verbeke J, De Bolle X, Arnould T. When mitophagy dictates the outcome of cellular infection: the case of Brucella abortus. Autophagy. 2023 Aug 17:1-2.

Verbeke J, De Bolle X, Arnould T. To eat or not to eat mitochondria? How do host cells cope with mitophagy upon bacterial infection? PLoS Pathog. 2023 Jul 6;19(7):e1011471.

Verbeke J, Fayt Y, Martin L, Yilmaz O, Sedzicki J, Reboul A, Jadot M, Renard P, Dehio C, Renard HF, Letesson JJ, De Bolle X, Arnould T. Host cell egress of Brucella abortus requires BNIP3L-mediated mitophagy. EMBO J. 2023 Jul 17;42(14):e112817.

Servais C, Vassen V, Verhaeghe A, Küster N, Carlier E, Phégnon L, Mayard A, Auberger N, Vincent S, De Bolle X. Lipopolysaccharide biosynthesis and traffic in the envelope of the pathogen Brucella abortus. Nat Commun. 2023 Feb 17;14(1):911.

Roba A, Carlier E, Godessart P, Naili C, De Bolle X. A histidine auxotroph mutant is defective for cell separation and allows the identification of crucial factors for cell division in Brucella abortus. Mol Microbiol. 2022 Jun 24.

Potemberg G, Demars A, Barbieux E, Reboul A, Stubbe FX, Galia M, Lagneaux M, Comein A, Denis O, Pérez-Morga D, Vanderwinden JM, De Bolle X, Muraille E. Genome-wide analysis of Brucella melitensis genes required throughout intranasal infection in mice. PLoS Pathog. 2022 Jun 30;18(6):e1010621.

Reboul A, Carlier E, Stubbe FX, Barbieux É, Demars A, Ong TAP, Gerodez A, Muraille E, De Bolle X. PdeA is required for the rod shape morphology of Brucella abortus. Mol Microbiol. 2021 Dec;116(6):1449-1463.

Godessart P, Lannoy A, Dieu M, Van der Verren SE, Soumillion P, Collet JF, Remaut H, Renard P, De Bolle X. β-Barrels covalently link peptidoglycan and the outer membrane in the α-proteobacterium Brucella abortus. Nat Microbiol. 2021 Jan;6(1):27-33.

Van der Henst M, Carlier E, De Bolle X. Intracellular Growth and Cell Cycle Progression are Dependent on (p)ppGpp Synthetase/Hydrolase in Brucella abortus. Pathogens. 2020 Jul 14;9(7):E571.

Demars A, Lison A, Machelart A, Van Vyve M, Potemberg G, Vanderwinden JM, De Bolle X, Letesson JJ, Muraille E. Route of Infection Strongly Impacts the Host-Pathogen Relationship. Front Immunol. 2019 Jul 11;10:1589.

Poncin K, Roba A, Jimmidi R, Potemberg G, Fioravanti A, Francis N, Willemart K, Zeippen N, Machelart A, Biondi EG, Muraille E, Vincent SP, De Bolle X. Occurrence and repair of alkylating stress in the intracellular pathogen Brucella abortus. Nat Commun. 2019 Oct 24;10(1):4847.

Vassen V, Valotteau C, Feuillie C, Formosa-Dague C, Dufrêne YF, De Bolle X. Localized incorporation of outer membrane components in the pathogen Brucella abortus. EMBO J. 2019 Mar 1;38(5).

Sternon JF, Godessart P, Gonçalves de Freitas R, Van der Henst M, Poncin K, Francis N, Willemart K, Christen M, Christen B, Letesson JJ, De Bolle X. Transposon sequencing of Brucella abortus uncovers essential genes for growth in vitro and inside macrophages. Infect Immun. 2018 Jul 23;86(8).

Poncin K, Gillet S, De Bolle X. Learning from the master: Targets and functions of the CtrA response regulator in Brucella abortus and other alpha-proteobacteria. FEMS Microbiol Rev. 2018 May 3.

Francis N, Poncin K, Fioravanti A, Vassen V, Willemart K, Ong TA, Rappez L, Letesson JJ, Biondi EG, De Bolle X. CtrA Controls Cell Division and Outer Membrane Composition of the Pathogen Brucella abortus. Mol Microbiol. 2017 Mar;103(5):780-797.

De Bolle X, Crosson S, Matroule JY, Letesson JJ. Brucella abortus Cell Cycle and Infection Are Coordinated. Trends Microbiol. 2015 Dec;23(12):812-821.