Stochastic Self-Assembly of ParB Proteins Builds the Bacterial DNA Segregation Apparatus Auteur(s): Sanchez Aurore, Cattoni Diego, Walter J.-C., Rech Jérôme, Parmeggiani A., Nollmann Marcelo, Bouet Jean-Yves (Article) Publié: Cell Systems, vol. 1 p.163-173 (2015) Texte intégral en Openaccess : Ref HAL: hal-01191677_v1 DOI: 10.1016/j.cels.2015.07.013 WoS: 000209925700010 Exporter : BibTex | endNote 60 Citations Résumé: Many canonical processes in molecular biology rely on the dynamic assembly of higher-order nucleoprotein complexes. In bacteria, the assembly mechanism of ParABS, the nucleoprotein super-complex that actively segregates the bacterial chromosome and many plasmids, remains elusive. We combined super-resolution microscopy, quantitative genome-wide surveys, biochemistry, and mathematical modeling to investigate the assembly of ParB at the centromere-like sequences parS. We found that nearly all ParB molecules are actively confined around parS by a network of synergistic protein-protein and protein-DNA interactions. Interrogation of the empirically determined, high-resolution ParB genomic distribution with modeling suggests that instead of binding only to specific sequences and subsequently spreading, ParB binds stochastically around parS over long distances. We propose a new model for the formation of the ParABS partition complex based on nucleation and caging: ParB forms a dynamic lattice with the DNA around parS.This assembly model and approach to characterizing large-scale, dynamic interactions between macro-molecules may be generalizable to many unrelated machineries that self-assemble in superstructures. |