title: Functional polarization of the Escherichia coli chromosome terminus: the dif site acts in chromosome dimer resolution only when located between long stretches of opposite polarity.
abstract: In Escherichia coli, chromosome dimers are generated by recombination between circular sister chromosomes. Dimers are lethal unless resolved by a system that involves the XerC, XerD and FtsK proteins acting at a site (dif) in the terminus region. Resolution fails if dif is moved from its normal position. To analyse this positional requirement, dif was transplaced to a variety of positions, and deletions and inversions of portions of the dif region were constructed. Resolution occurs only when dif is located at the convergence of multiple, oppositely polarized DNA sequence elements, inferred to lie in the terminus region. These polar elements may position dif at the cell septum and be general features of chromosome organization with a role in nucleoid dynamics.
authors.affiliation: Laboratoire de Microbiologie et de Génétique moléculaires, Centre National de la Recherche Scientifique, 118 route de Narbonne, 31062 Toulouse Cedex, France.
authors.forename: K
authors.initials: K
authors.lastname: Pérals
authors.forename: F
authors.initials: F
authors.lastname: Cornet
authors.forename: Y
authors.initials: Y
authors.lastname: Merlet
authors.forename: I
authors.initials: I
authors.lastname: Delon
authors.forename: J M
authors.initials: JM
authors.lastname: Louarn
mesh_terms: D001665:Binding Sites; D007446:Chromosome Inversion; D002876:Chromosomes, Bacterial; D004254:DNA Nucleotidyltransferases / Q000378:metabolism; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism*; D004270:DNA, Circular / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D019426:Integrases; D008565:Membrane Proteins / Q000378:metabolism; D008957:Models, Genetic; D011485:Protein Binding; D045522:Recombinases
chemical_list: D004269:DNA, Bacterial; D004270:DNA, Circular; D029968:Escherichia coli Proteins; C096452:FtsK protein, E coli; D008565:Membrane Proteins; D045522:Recombinases; C473360:XerC protein, E coli; D004254:DNA Nucleotidyltransferases; D019426:Integrases; C473361:XerD protein, E coli; C115006:integron integrase IntI1