Y. Fedor, J. Vignard, M.-L. Nicolau-Travers, E. Boutet-Robinet, C. Watrin, B. Salles and G. Mirey
The Cytolethal Distending Toxin (CDT), virulence factor produced by several pathogenic bacteria, induces DNA double-strand breaks (DSB) and cell cycle arrest in G2/M phase. We demonstrate that Escherichia coli CDT progressively induces DSB, mostly in S-phase cells, at low doses (50 pg.ml-1 or LD50). These are preceeded by single-strand breaks, converted into DSB through a replicative stress. Furthermore, the homologous recombination Rad51 protein is mobilized to these S-phase-associated DSB, unveiling a new mechanism of action for the CDT genotoxin.