Nicolas Mirouze

Genetic competence for natural transformation, considered one of the three main mechanisms leading to horizontal gene transfer in bacteria, is able to promote evolution, through genomic plasticity, and foster antibiotic resistance and virulence factors spreading. Conserved machinery and actors required to perform natural transformation have been shown to accumulate at different cellular localizations depending on the model organism considered. In this study, we investigate the transformation apparatus composition, localization, and dynamics in the human pathogen Staphylococcus aureus . We particularly show that most of the natural transformation actors co-localize in clusters. We also reveal that the localization of natural transformation proteins is dynamic, following the cell cycle. Ultimately, the natural transformation apparatus is preferentially established in the vicinity of the division septum. All these results demonstrate that DNA binding, uptake, and recombination are spatially and temporally coordinated to ensure S. aureus natural transformation. Finally, we hypothesize that S. aureus competent cells would initiate and then block cell division to ensure the success of natural transformation before the final constriction of the cytokinetic ring. IMPORTANCE Natural transformation, considered one of the three main mechanisms leading to horizontal gene transfer in bacteria, is able to promote genomic plasticity and foster antibiotic resistance spreading. Conserved machinery and actors required to perform natural transformation have been shown to accumulate at different cellular localizations depending on the model organism considered. Here, we show in the human pathogen Staphylococcus aureus that DNA binding, uptake, and recombination are spatially and temporally coordinated to ensure S. aureus natural transformation. We also reveal that localization of natural transformation proteins occurs in the vicinity of the division septum allowing S. aureus competent cells to block cell division to ensure the success of natural transformation before the final constriction of the cytokinetic ring.