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Updated: May 11, 2026
07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
PriC-mediated DNA replication restart requires PriC complex formation with the single-stranded DNA-binding protein
Sarah R Wessel1, Aimee H Marceau, Shawn C Massoni
1Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA.
The Journal of Biological Chemistry
|May 1, 2013
Summary
DNA replication restart is crucial for bacterial survival. This study reveals how PriC protein interacts with single-stranded DNA-binding protein (SSB) to reload replication machinery onto stalled forks, ensuring genome stability.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- DNA replication fork progression is often impeded by obstacles, leading to replisome ejection.
- Unrepaired replisome ejection causes bacterial cell death, necessitating DNA replication restart mechanisms.
- Bacteria employ specialized proteins to reload replisomes onto abandoned replication forks.
Purpose of the Study:
- To define the interaction between PriC, a DNA replication restart protein, and SSB, a single-stranded DNA-binding protein.
- To elucidate the role of the PriC/SSB interaction in reloading the DnaB helicase onto abandoned replication forks.
Main Methods:
- In vitro biochemical assays to test PriC/SSB complex formation and DnaB helicase loading.
- Site-directed mutagenesis to identify key residues in the PriC/SSB interaction.
- Single-molecule experiments to observe the effect of PriC on SSB/DNA complexes.
Main Results:
- A direct interaction between PriC and SSB was identified, requiring conserved residues on both proteins.
- Disruption of the PriC/SSB interface blocked DnaB helicase reloading in vitro.
- PriC variants unable to bind SSB were non-functional in vivo.
- PriC binding to SSB alters SSB/DNA complexes, exposing single-stranded DNA.
Conclusions:
- PriC directly interacts with SSB, forming a complex essential for DNA replication restart.
- This interaction is critical for remodeling SSB/DNA complexes at stalled forks, creating a platform for DnaB helicase loading.
- The PriC/SSB interaction is a key step in bacterial DNA replication restart, ensuring genome integrity.
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