NAmur Research Institute for LIfe Sciences
Xavier De Bolle
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 | ResearchGate | www.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 researchers: Dr. Aitor Elizalde-Bielsa, Dr. Katy Poncin and Dr. Linus Wilhelm
PhD students: Kejsi Dervishi, Jonathan De Stercke, Charline Focant, Adélie Lannoy, Thomas Rouma and Audrey Verhaeghe
Lab technician: Ena Shehu
Research projects
- ONGOING WELBIO project | Lipopolysaccharide O-chain biosynthesis in Brucella abortus: from fundamental knowledge to synthetic microbiology. Ongoing PhD thesis by Kejsi Dervishi. Postdoctoral research by Dr. Aitor Elizalde-Bielsa and Dr. Linus Wilhelm. Technical support by Ena Shehu.
- 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.
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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 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).
- . PhD thesis defended by Adélie Lannoy on 24/01/2025.
- Development of vaccine candidates against Brucella melitensis and Acinetobacter baumannii infections in a mouse model. PhD thesis defended by Emeline Barbieux on 23/11/2023. Under co-supervision by Prof. Eric Muraille, ULB (promoter), Prof. Xavier De Bolle, UNamur (promoter) and Prof. Laurence Van Melderen, ULB (co-promoter).
- Smooth lipopolysaccharide biosynthesis, unipolar growth and disulfide bond formation in Brucella abortus cell envelope. PhD thesis defended by Caroline Servais on 27/02/2023.
- Involvement of cyclic-diGMP on Brucella abortus cell morphology and infection. Postdoctoral research by Angéline Reboul (Oct 2017 - 2022).
- Study of the mechanisms leading to mitochondrial fragmentation and mitophagy in Brucella-infected cells and analysis of its functional consequences. PhD thesis defended by Jérémy Verbeke on 30/03/2023. Under co-supervision by Prof. Thierry Arnould (promoter) and Prof. Xavier De Bolle (co-promoter).
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Histidine biosynthesis, cell separation and copper resistance in Brucella abortus. PhD thesis defended by Agnès Roba on 04/02/2022.
- Interactions between the outer-membrane and the peptidoglycan in Brucella abortus. PhD thesis defended by Pierre Godessart on 17/12/2021.
- Characterization of the early immune response against intranasal Brucella infection in mice. PhD thesis defended by Aurore Demars on 14/12/2020. Under co-supervision by Prof. Xavier De Bolle, UNamur (promoter) and Prof. Eric Muraille, ULB (promoter).
- Identification of bacterial genes indispensable to the early phase of pulmonary infection by Brucella melitensis in mice. PhD thesis defended by Georges Potemberg on 16/04/2020. Under co-supervision by Prof. Xavier De Bolle, UNamur (promoter) and Prof. Eric Muraille, ULB (promoter).
- ACtIVAtE: The virulence potential of human pathogens: how Acinetobacter baumannii survives Acanthamoeba castellanii predation. Postdoctoral research by Charles Van der Henst (Jan 2018 - Dec 2019). Under co-supervision by Prof. Xavier De Bolle, UNamur, NARILIS and Prof. Karine Van Doninck, UNamur, ILEE.
- Study of the replication control and polarity in Brucella abortus. PhD thesis defended by Mathilde Van der Henst on 15/11/2019.
- Alkylating stress on Brucella abortus in culture and in infection renewal. PhD thesis defended by Katy Poncin on 11/12/2018.
- Brucellosis at a livestock/human/wildlife interface in South Africa: understanding the epidemiology and control. PhD thesis defended by Grégory Simpson on 28/11/2018. Under co-supervision by Prof. Xavier De Bolle, UNamur (promoter) and Prof. Jacques Godfroid, UiT The Arctic University of Norway (co-promoter).
- Localization of envelope growth in Brucella abortus renewal. PhD thesis defended by Victoria Vassen on 23/11/2018.
- Growth control of Brucella abortus in human trophoblasts JEG-3 cells. PhD thesis defended by Thi Anh Phuong Ong on 18/12/2017.
- Tn-seq on the pathogen Brucella abortus uncovers essential functions for culture and critical pathways for macrophages infection including pyrimidines biosynthesis. PhD thesis defended by Jean-François Sternon on 18/10/2017.
- CtrA-dependant cell cycle regulation of Brucella abortus in culture and during infection. PhD thesis defended by Nayla Francis on 01/12/2015.
Selected publications
Lacritick M, Reboul A, Yahia Boudhar R, Carlier E, Fairman JW, Scaillet T, Subramanian S, Wouters J, Staker B, De Bolle X, Vincent SP. Site-Specific Incorporation of Clickable d-Mannose Derivatives in the Lipopolysaccharide Core of the Pathogen Brucella abortus. ACS Chem Biol. 2025 Jun 20;20(6):1382-1393.
Barbieux E, Potemberg G, Stubbe FX, Fraikin A, Poncin K, Reboul A, Rouma T, Zúñiga-Ripa A, De Bolle X, Muraille E. Genome-wide analysis of Brucella melitensis growth in spleen of infected mice allows rational selection of new vaccine candidates. PLoS Pathog. 2024 Aug 26;20(8):e1012459.
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.
