title: A three-dimensional ParF meshwork assembles through the nucleoid to mediate plasmid segregation.
abstract: Genome segregation is a fundamental step in the life cycle of every cell. Most bacteria rely on dedicated DNA partition proteins to actively segregate chromosomes and low copy-number plasmids. Here, by employing super resolution microscopy, we establish that the ParF DNA partition protein of the ParA family assembles into a three-dimensional meshwork that uses the nucleoid as a scaffold and periodically shuttles between its poles. Whereas ParF specifies the territory for plasmid trafficking, the ParG partner protein dictates the tempo of ParF assembly cycles and plasmid segregation events by stimulating ParF adenosine triphosphate hydrolysis. Mutants in which this ParG temporal regulation is ablated show partition deficient phenotypes as a result of either altered ParF structure or dynamics and indicate that ParF nucleoid localization and dynamic relocation, although necessary, are not sufficient per se to ensure plasmid segregation. We propose a Venus flytrap model that merges the concepts of ParA polymerization and gradient formation and speculate that a transient, dynamic network of intersecting polymers that branches into the nucleoid interior is a widespread mechanism to distribute sizeable cargos within prokaryotic cells.
authors.affiliation: Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
authors.forename: Brett N
authors.initials: BN
authors.lastname: McLeod
authors.affiliation: Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
authors.forename: Gina E
authors.initials: GE
authors.lastname: Allison-Gamble
authors.affiliation: Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
authors.forename: Madhuri T
authors.initials: MT
authors.lastname: Barge
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Duke University, Durham, NC 27710, USA.
authors.forename: Nam K
authors.initials: NK
authors.lastname: Tonthat
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Duke University, Durham, NC 27710, USA.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Schumacher
authors.affiliation: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
authors.forename: Finbarr
authors.initials: F
authors.lastname: Hayes
authors.affiliation: Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
authors.forename: Daniela
authors.initials: D
authors.lastname: Barillà
mesh_terms: D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009154:Mutation; D010957:Plasmids / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000032:analysis / Q000235:genetics; D059008:Time-Lapse Imaging
chemical_list: D029968:Escherichia coli Proteins; C504447:ParG protein, E coli; D012097:Repressor Proteins; D004247:DNA; D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase; C495091:plsC protein, E coli