title: Chromosomal organization and segregation in Pseudomonas aeruginosa.
abstract: The study of chromosomal organization and segregation in a handful of bacteria has revealed surprising variety in the mechanisms mediating such fundamental processes. In this study, we further emphasized this diversity by revealing an original organization of the Pseudomonas aeruginosa chromosome. We analyzed the localization of 20 chromosomal markers and several components of the replication machinery in this important opportunistic γ-proteobacteria pathogen. This technique allowed us to show that the 6.3 Mb unique circular chromosome of P. aeruginosa is globally oriented from the old pole of the cell to the division plane/new pole along the oriC-dif axis. The replication machinery is positioned at mid-cell, and the chromosomal loci from oriC to dif are moved sequentially to mid-cell prior to replication. The two chromosomal copies are subsequently segregated at their final subcellular destination in the two halves of the cell. We identified two regions in which markers localize at similar positions, suggesting a bias in the distribution of chromosomal regions in the cell. The first region encompasses 1.4 Mb surrounding oriC, where loci are positioned around the 0.2/0.8 relative cell length upon segregation. The second region contains at least 800 kb surrounding dif, where loci show an extensive colocalization step following replication. We also showed that disrupting the ParABS system is very detrimental in P. aeruginosa. Possible mechanisms responsible for the coordinated chromosomal segregation process and for the presence of large distinctive regions are discussed.
authors: CNRS, Centre de Génétique Moléculaire, UPR3404, Gif-sur-Yvette, France. vallet@cgm.cnrs-gif.fr
authors: Isabelle
authors: I
authors: Vallet-Gely
authors: Frédéric
authors: F
authors: Boccard
mesh_terms: D002874:Chromosome Mapping; D020090:Chromosome Segregation / Q000235:genetics; D022004:Chromosome Structures; D002876:Chromosomes, Bacterial / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics*; D004270:DNA, Circular / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D051738:Origin Recognition Complex / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000235:genetics*
chemical_list: D004270:DNA, Circular; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex
references: Front Biosci (Landmark Ed). 2012 Jan 01;17:1020-34
references: 22201788
references: Nat Methods. 2012 Apr 08;9(5):480-2
references: 22484850
references: Cell. 2005 Jun 17;121(6):899-911
references: 15960977
references: Mol Microbiol. 2006 Oct;62(2):331-8
references: 17020576
references: Plasmid. 2006 May;55(3):194-200
references: 16376988
references: Cell. 2009 May 15;137(4):697-707
references: 19450517
references: Biochimie. 2010 Dec;92(12):1715-21
references: 20615449
references: EMBO J. 2001 Sep 3;20(17):4952-63
references: 11532959
references: Mol Microbiol. 2003 Aug;49(3):731-43
references: 12864855
references: Cell. 2008 Oct 31;135(3):475-85
references: 18984159
references: J Bacteriol. 2006 Feb;188(3):1060-70
references: 16428410
references: Microbiol Rev. 1996 Sep;60(3):539-74
references: 8840786
references: Microbiology (Reading). 2009 Apr;155(Pt 4):1080-1092
references: 19332810
references: Proc Natl Acad Sci U S A. 2008 Oct 7;105(40):15435-40
references: 18824683
references: Mol Microbiol. 2003 Nov;50(3):825-34
references: 14617144
references: J Bacteriol. 2006 Mar;188(6):2244-53
references: 16513754
references: Cell. 2008 Sep 19;134(6):945-55
references: 18805088
references: Proc Natl Acad Sci U S A. 2004 Jun 22;101(25):9257-62
references: 15178755
references: Proc Natl Acad Sci U S A. 1990 Feb;87(4):1278-82
references: 2106132
references: Genes Dev. 2005 Oct 1;19(19):2367-77
references: 16204186
references: J Struct Biol. 2006 Nov;156(2):292-303
references: 16860572
references: J Bacteriol. 2007 Aug;189(15):5762-72
references: 17545287
references: Science. 1998 Nov 20;282(5393):1516-9
references: 9822387
references: Mol Microbiol. 2011 Aug;81(4):881-96
references: 21752107
references: Cell. 2008 Sep 19;134(6):956-68
references: 18805089
references: Cell. 2009 May 15;137(4):685-96
references: 19450516
references: Science. 2003 Jan 24;299(5606):532-6
references: 12493822
references: Nat Rev Microbiol. 2010 Aug;8(8):600-7
references: 20634810
references: Mol Microbiol. 2011 May;80(3):612-27
references: 21414037
references: Genes Dev. 2000 Jan 15;14(2):212-23
references: 10652275
references: Mol Microbiol. 2008 Jun;68(6):1418-27
references: 18410497
references: Genes Dev. 2001 Aug 15;15(16):2031-41
references: 11511534
references: Nature. 2000 Aug 31;406(6799):959-64
references: 10984043
references: Cold Spring Harb Perspect Biol. 2010 Feb;2(2):a000349
references: 20182613
references: Cell. 2008 Apr 4;133(1):90-102
references: 18394992
references: J Bacteriol. 2004 Oct;186(20):6983-98
references: 15466051
references: Genes Dev. 2006 Dec 1;20(23):3269-82
references: 17158745
references: EMBO J. 2004 Oct 27;23(21):4330-41
references: 15470498
references: Genes Dev. 2012 Oct 15;26(20):2348-60
references: 23070816
references: EMBO J. 2012 May 11;31(14):3198-211
references: 22580828
references: Mol Microbiol. 2011 Aug;81(3):676-88
references: 21651626
references: J Bacteriol. 2003 Feb;185(4):1326-37
references: 12562803
references: FEMS Microbiol Rev. 2011 Jul;35(4):652-80
references: 21361996
references: Clin Microbiol Rev. 2009 Oct;22(4):582-610
references: 19822890