1. Biochemistry and Chemical Biology
  2. Chromosomes and Gene Expression
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Frequent exchange of the DNA polymerase during bacterial chromosome replication

  1. Thomas R Beattie
  2. Nitin Kapadia
  3. Emilien Nicolas
  4. Stephan Uphoff
  5. Adam JM Wollman
  6. Mark C Leake
  7. Rodrigo Reyes-Lamothe  Is a corresponding author
  1. McGill University, Canada
  2. Fast Track Diagnostics Luxembourg S.à.r.l, Luxembourg
  3. University of Oxford, United Kingdom
  4. University of York, United Kingdom
Research Article
  • Cited 66
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Cite this article as: eLife 2017;6:e21763 doi: 10.7554/eLife.21763

Abstract

The replisome is a multiprotein machine that carries out DNA replication. In Escherichia coli, a single pair of replisomes is responsible for duplicating the entire 4.6 Mbp circular chromosome (Beattie and Reyes-Lamothe, 2015). In vitro studies of reconstituted E. coli replisomes have attributed this remarkable processivity to the high stability of the replisome once assembled on DNA (Tanner et al., 2011, Yao et al., 2009, Kim et al., 1996b). By examining replisomes in live E. coli with fluorescence microscopy, we found that the Pol III* subassembly frequently disengages from the replisome during DNA synthesis and exchanges with free copies from solution. In contrast, the DnaB helicase associates stably with the replication fork, providing the molecular basis for how the E. coli replisome can maintain high processivity and yet possess the flexibility to bypass obstructions in template DNA. Our data challenges the widely-accepted semi-discontinuous model of chromosomal replication, instead supporting a fully discontinuous mechanism in which synthesis of both leading and lagging strands is frequently interrupted.

Article and author information

Author details

  1. Thomas R Beattie

    Department of Biology, McGill University, Montreal, Canada
    Competing interests
    The authors declare that no competing interests exist.
  2. Nitin Kapadia

    Department of Biology, McGill University, Montreal, Canada
    Competing interests
    The authors declare that no competing interests exist.
  3. Emilien Nicolas

    Fast Track Diagnostics Luxembourg S.à.r.l, Luxembourg, Luxembourg
    Competing interests
    The authors declare that no competing interests exist.
  4. Stephan Uphoff

    Department of Biochemistry, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  5. Adam JM Wollman

    Biological Physical Sciences Institute, University of York, York, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  6. Mark C Leake

    Biological Physical Sciences Institute, University of York, York, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  7. Rodrigo Reyes-Lamothe

    Department of Biology, McGill University, Montreal, Canada
    For correspondence
    rodrigo.reyes@mcgill.ca
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5330-3481

Funding

Natural Sciences and Engineering Research Council of Canada (Discovery Grant,435521-2013)

  • Thomas R Beattie
  • Nitin Kapadia
  • Rodrigo Reyes-Lamothe

Canada Research Chairs (Tier II,950-228994)

  • Rodrigo Reyes-Lamothe

Canadian Institutes of Health Research (Operating Grant,142473)

  • Thomas R Beattie
  • Nitin Kapadia
  • Rodrigo Reyes-Lamothe

Canada Foundation for Innovation (Leaders Oportunity Fund,228994)

  • Thomas R Beattie
  • Nitin Kapadia
  • Rodrigo Reyes-Lamothe

Wellcome (Junior Research Fellowship)

  • Stephan Uphoff

Biotechnology and Biological Sciences Research Council (BBSRC# BB/N006453/1)

  • Adam JM Wollman
  • Mark C Leake

Medical Research Council (MRC# MR/K01580X/1)

  • Adam JM Wollman
  • Mark C Leake

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. James M Berger, Johns Hopkins University School of Medicine, United States

Publication history

  1. Received: September 22, 2016
  2. Accepted: March 28, 2017
  3. Accepted Manuscript published: March 31, 2017 (version 1)
  4. Version of Record published: April 24, 2017 (version 2)

Copyright

© 2017, Beattie et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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