title: Differential management of the replication terminus regions of the two Vibrio cholerae chromosomes during cell division.
abstract: The replication terminus region (Ter) of the unique chromosome of most bacteria locates at mid-cell at the time of cell division. In several species, this localization participates in the necessary coordination between chromosome segregation and cell division, notably for the selection of the division site, the licensing of the division machinery assembly and the correct alignment of chromosome dimer resolution sites. The genome of Vibrio cholerae, the agent of the deadly human disease cholera, is divided into two chromosomes, chrI and chrII. Previous fluorescent microscopy observations suggested that although the Ter regions of chrI and chrII replicate at the same time, chrII sister termini separated before cell division whereas chrI sister termini were maintained together at mid-cell, which raised questions on the management of the two chromosomes during cell division. Here, we simultaneously visualized the location of the dimer resolution locus of each of the two chromosomes. Our results confirm the late and early separation of chrI and chrII Ter sisters, respectively. They further suggest that the MatP/matS macrodomain organization system specifically delays chrI Ter sister separation. However, TerI loci remain in the vicinity of the cell centre in the absence of MatP and a genetic assay specifically designed to monitor the relative frequency of sister chromatid contacts during constriction suggest that they keep colliding together until the very end of cell division. In contrast, we found that even though it is not able to impede the separation of chrII Ter sisters before septation, the MatP/matS macrodomain organization system restricts their movement within the cell and permits their frequent interaction during septum constriction.
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Demarre
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Galli
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: Leila
authors.initials: L
authors.lastname: Muresan
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Paly
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: Ariane
authors.initials: A
authors.lastname: David
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Possoz
authors.affiliation: CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France; Université Paris-Sud, Orsay, France.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Barre
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002455:Cell Division; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D011995:Recombination, Genetic; D012854:Sister Chromatid Exchange; D059008:Time-Lapse Imaging; D014734:Vibrio cholerae / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D002868:Chromosomal Proteins, Non-Histone