title: Polymer modeling of the E. coli genome reveals the involvement of locus positioning and macrodomain structuring for the control of chromosome conformation and segregation.
abstract: The mechanisms that control chromosome conformation and segregation in bacteria have not yet been elucidated. In Escherichia coli, the mere presence of an active process remains an open question. Here, we investigate the conformation and segregation pattern of the E. coli genome by performing numerical simulations on a polymer model of the chromosome. We analyze the roles of the intrinsic structuring of chromosomes and the forced localization of specific loci, which are observed in vivo. Specifically, we examine the segregation pattern of a chromosome that is divided into four structured macrodomains (MDs) and two non-structured regions. We find that strong osmotic-like organizational forces, which stem from the differential condensation levels of the chromosome regions, dictate the cellular disposition of the chromosome. Strikingly, the comparison of our in silico results with fluorescent imaging of the chromosome choreography in vivo reveals that in the presence of MDs the targeting of the origin and terminus regions to specific positions are sufficient to generate a segregation pattern that is indistinguishable from experimentally observed patterns.
authors.affiliation: Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain, CGM-CNRS, Université Paris-Sud, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France and CIRB - Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: Junier
authors.forename: Frédéric
authors.initials: F
authors.lastname: Boccard
authors.forename: Olivier
authors.initials: O
authors.lastname: Espéli
mesh_terms: D002453:Cell Cycle; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial / Q000737:chemistry*; D004269:DNA, Bacterial / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics*; D056426:Genetic Loci; D016680:Genome, Bacterial; D008957:Models, Genetic
chemical_list: D004269:DNA, Bacterial