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Frequent exchange of the DNA polymerase during bacterial chromosome replication

Lookup NU author(s): Dr Adam WollmanORCiD

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Abstract

© Beattie et al. 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. In vitro studies of reconstituted E. coli replisomes have attributed this remarkable processivity to the high stability of the replisome once assembled on DNA. 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 semidiscontinuous model of chromosomal replication, instead supporting a fully discontinuous mechanism in which synthesis of both leading and lagging strands is frequently interrupted.

Publication metadata

Author(s): Beattie TR, Kapadia N, Nicolas E, Uphoff S, Wollman AJM, Leake MC, Reyes-Lamothe R

Publication type: Article

Publication status: Published

Journal: eLife

Year: 2017

Volume: 6

Online publication date: 31/03/2017

Acceptance date: 28/03/2017

Date deposited: 10/02/2020

ISSN (electronic): 2050-084X

Publisher: eLife Sciences Publications Ltd

URL: https://doi.org/10.7554/eLife.21763

DOI: 10.7554/eLife.21763

PubMed id: 28362256

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