Transcription leads to pervasive replisome instability in bacteria

Abstract
Article and author information
Metrics

Abstract

The canonical model of DNA replication describes a highly-processive and largely continuous process by which the genome is duplicated. This continuous model is based upon in vitro reconstitution and in vivo ensemble experiments. Here, we characterize the replisome-complex stoichiometry and dynamics with single-molecule resolution in bacterial cells. Strikingly, the stoichiometries of the replicative helicase, DNA polymerase, and clamp loader complexes are consistent with the presence of only one active replisome in a significant fraction of cells (>40%). Furthermore, many of the observed complexes have short lifetimes (<8 minutes), suggesting that replisome disassembly is quite prevalent, possibly occurring several times per cell cycle. The instability of the replisome complex is conflict-induced: transcription inhibition stabilizes these complexes, restoring the second replisome in many of the cells. Our results suggest that, in contrast to the canonical model, DNA replication is a largely discontinuous process in vivo due to pervasive replication-transcription conflicts.

Article and author information

Author details

Sarah Mangiameli

Department of Physics, University of Washington, Seattle, United States

Competing interests
The authors declare that no competing interests exist.
Christopher N Merrikh

Department of Microbiology, University of Washington, Seattle, United States

Competing interests
The authors declare that no competing interests exist.
Paul A Wiggins

Department of Physics, University of Washington, Seattle, United States

For correspondence
pwiggins@uw.edu

Competing interests
The authors declare that no competing interests exist.
Houra Merrikh

Department of Microbiology, University of Washington Medical Center, Seattle, United States

For correspondence
merrikh@uw.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-9956-9640

Funding

National Science Foundation (MCB1243492.)

Sarah Mangiameli
Christopher N Merrikh
Paul A Wiggins
Houra Merrikh

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

Copyright

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.