Pneumococcal competence and transformation

Presentation

The pneumococcal competence and transformation team combines complementary approaches to study all aspects of competence and genetic transformation in the human pathogen Streptococcus pneumoniae (the pneumococcus). Pneumococcal competence is a transient genetic programme induced in response to stresses. Comeptence promotes transformation, a mechanism of horizontal gene transfer entirely encoded by the recipient cell. It involves capture of exogenous DNA, internalization in the form of single strands and integration into the recipient chromosome by homologous recombination, driven by the recombinase RecA. This process is widespread in the bacterial kingdom and promotes acquisition of new genetic traits. In the pneumococcus, transformation can mediate the spread of antibiotics and vaccine escape. Our team combines molecular genetics, cell biology, biochemistry and single molecule analyses to study the pneumococcal transformation process. The main projects of our team focus on:

• The functional dissection of competence regulation.
• The functional dissection of the mechanism of transformation.
• A study of how competence and transformation are integrated into the cell cycle.

Through these complementary projects, we aim to further our fundamental understanding of this widespread, clinically relevant process.

Projets

Publications

• Calum H G Johnston, Rachel Hope, Anne-Lise Soulet, Marie Dewailly, David De Lemos, Patrice Polard.
  The RecA-directed recombination pathway of natural transformation initiates at chromosomal replication forks in the pneumococcus
  Proceedings of the National Academy of Sciences (PNAS)
  2023 Feb
• Maud Hertzog, Thomas Noé Perry, Pauline Dupaigne, Sandra Serres, Violette Morales, Anne-Lise Soulet, Jason C Bell, Emmanuel Margeat, Stephen C Kowalczykowski, Eric Le Cam, Rémi Fronzes, Patrice Polard.
  Assembly mechanism and cryoEM structure of RecA recombination nucleofilaments from Streptococcus pneumoniae
  Nucleic Acids Research
  2023 Feb
• Vanessa Khemici, Marc Prudhomme, Patrice Polard.
  Tight Interplay between Replication Stress and Competence Induction in Streptococcus pneumoniae
  Cells
  2021 Jul
• Johnston CHG, Soulet AL, Bergé M, Prudhomme M, De Lemos D, Polard P..
  The alternative sigma factor σX mediates competence shut-off at the cell pole in Streptococcus pneumoniae
  eLife
  2020 Nov
• Jun Kurushima, Nathalie Campo, Renske van Raaphorst, Guillaume Cerckel, Patrice Polard, Jan-Willem Veening.
  Unbiased homeologous recombination during pneumococcal transformation allows for multiple chromosomal integration events
  Elife
  2020 Sep

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Funding