title: Evidence for a DNA-relay mechanism in ParABS-mediated chromosome segregation.
abstract: The widely conserved ParABS system plays a major role in bacterial chromosome segregation. How the components of this system work together to generate translocation force and directional motion remains uncertain. Here, we combine biochemical approaches, quantitative imaging and mathematical modeling to examine the mechanism by which ParA drives the translocation of the ParB/parS partition complex in Caulobacter crescentus. Our experiments, together with simulations grounded on experimentally-determined biochemical and cellular parameters, suggest a novel 'DNA-relay' mechanism in which the chromosome plays a mechanical function. In this model, DNA-bound ParA-ATP dimers serve as transient tethers that harness the elastic dynamics of the chromosome to relay the partition complex from one DNA region to another across a ParA-ATP dimer gradient. Since ParA-like proteins are implicated in the partitioning of various cytoplasmic cargos, the conservation of their DNA-binding activity suggests that the DNA-relay mechanism may be a general form of intracellular transport in bacteria.DOI: http://dx.doi.org/10.7554/eLife.02758.001.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States Microbial Diversity Institute, Yale University, West Haven, United States.
authors.forename: Hoong Chuin
authors.initials: HC
authors.lastname: Lim
authors.affiliation: Microbial Diversity Institute, Yale University, West Haven, United States Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States Howard Hughes Medical Institute, Yale University, New Haven, United States.
authors.forename: Ivan Vladimirovich
authors.initials: IV
authors.lastname: Surovtsev
authors.affiliation: Department of Mathematics, Louisiana State University, Baton Rouge, United States Howard Hughes Medical Institute, Yale University, New Haven, United States.
authors.forename: Bruno Gabriel
authors.initials: BG
authors.lastname: Beltran
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States.
authors.forename: Fang
authors.initials: F
authors.lastname: Huang
authors.affiliation: Department of Cell Biology, Yale School of Medicine, New Haven, United States Department of Biomedical Engineering, Yale University, New Haven, United States.
authors.forename: Jörg
authors.initials: J
authors.lastname: Bewersdorf
authors.affiliation: Microbial Diversity Institute, Yale University, West Haven, United States Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States Howard Hughes Medical Institute, Yale University, New Haven, United States Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States christine.jacobs-wagner@yale.edu.
authors.forename: Christine
authors.initials: C
authors.lastname: Jacobs-Wagner
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D016935:Caulobacter crescentus / Q000235:genetics*; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial / Q000235:genetics* / Q000378:metabolism; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D056426:Genetic Loci; D007091:Image Processing, Computer-Assisted; D061848:Optical Imaging
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins
keywords: Caulobacter crescentus; DNA partitioning; Par system; chromosome dynamics; intracellular transport