A type IV pilus mediates DNA binding during natural transformation in Streptococcus pneumoniae.

Raphael Laurenceau (1) , Gérard Péhau-Arnaudet (1) , Sonia Baconnais (2) , Joseph Gault (3) , Christian Malosse (3) , Annick Dujeancourt (1) , Nathalie N. Campo (4) , Julia Chamot-Rooke (3) , Eric Le Cam (2) , Jean-Pierre Claverys (4) , Rémi Fronzes (1)

1 Biologie Structurale de la Sécrétion Bactérienne
2 UMR8126 - Signalisation, noyaux et innovations en cancérologie
3 Spectrométrie de Masse structurale et protéomique
4 LMGM - Laboratoire de microbiologie et génétique moléculaires - UMR5100

Natural genetic transformation is widely distributed in bacteria and generally occurs during a genetically programmed differentiated state called competence. This process promotes genome plasticity and adaptability in Gram-negative and Gram-positive bacteria. Transformation requires the binding and internalization of exogenous DNA, the mechanisms of which are unclear. Here, we report the discovery of a transformation pilus at the surface of competent Streptococcus pneumoniae cells. This Type IV-like pilus, which is primarily composed of the ComGC pilin, is required for transformation. We provide evidence that it directly binds DNA and propose that the transformation pilus is the primary DNA receptor on the bacterial cell during transformation in S. pneumoniae. Being a central component of the transformation apparatus, the transformation pilus enables S. pneumoniae, a major Gram-positive human pathogen, to acquire resistance to antibiotics and to escape vaccines through the binding and incorporation of new genetic material.

Domaines: Bactériologie

Raphael Laurenceau, Gérard Péhau-Arnaudet, Sonia Baconnais, Joseph Gault, Christian Malosse, et al.. A type IV pilus mediates DNA binding during natural transformation in Streptococcus pneumoniae.. PLoS Pathogens, 2013, 9 (6), pp.e1003473. ⟨10.1371/journal.ppat.1003473⟩. ⟨hal-02370135⟩