Brucella cell cycle and infection

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

Principal Investigator

Prof. Xavier De Bolle

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

Member of the Namur Research Pole in Infectiology (NaRePI)

Research portal UNamur  |  ORCID  |

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 include (i) the biogenesis and homeostasis of the enveloppe during polar growth and infection and (ii) the adaptations linked to histidine biosynthesis in the intracellular environment.

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. Angéline Reboul

PhD students: Emeline Barbieux, Charline Focant, Pierre Godessart, Adélie Lanoy, Agnès Roba, Caroline Servais and Jérémy Verbeke 

Research projects

  • ONGOING Study of the biogenesis of the VirB type IV secretion system in Brucella abortus. Ongoing PhD thesis by Charline Focant. Under the supervision of Prof. Xavier De Bolle, UNamur, NARILIS.
  • ONGOING Envelope stress response in Brucella abortus. Ongoing PhD thesis by Adélie Lanoy. Under the supervision of Prof. Xavier De Bolle, UNamur, NARILIS.
  • ONGOING Identification by transposon sequencing of essential bacterial genes for chronic infection by Brucella in mice and natural hosts. Ongoing PhD thesis by Emeline Barbieux. Under co-supervision by Prof. Eric Muraille, ULB (promoter), Prof. Xavier De Bolle, UNamur, NARILIS (promoter) and Prof. Laurence Van Melderen, ULB (co-promoter).
  • ONGOING Study of the mechanisms leading to mitochondrial fragmentation in Brucella-infected cells and analysis of its functional consequences. Ongoing PhD thesis by Jérémy Verbeke. Under co-supervision by Prof. Thierry Arnould, UNamur, NARILIS (promoter) and Prof. Xavier De Bolle, UNamur, NARILIS (co-promoter).
  • ONGOING Involvement of cyclic-diGMP on Brucella abortus cell morphology and infection. Postdoctoral research by Angéline Reboul. Under the supervision of Prof. Xavier De Bolle, UNamur, NARILIS.
  • ONGOING Biosynthetic adaptation of Brucella abortus inside host cells. Ongoing PhD thesis by Agnès Roba. Under the supervision of Prof. Xavier De Bolle, UNamur, NARILIS.
  • ONGOING Polar growth mechanism of Brucella abortus and disulfide bond formation in its periplasm. Ongoing PhD thesis by Caroline Servais. Under the supervision of Prof. Xavier De Bolle, UNamur, NARILIS.

Selected publications

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.