Primase Directs the Release of DnaC from DnaB

Makowska-Grzyska, M.; Kaguni, Jon M.

doi:10.1016/j.molcel.2009.12.031

Cited by 78 publications

(103 citation statements)

References 68 publications

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“…It is also possible that PriC binding to DnaB could stimulate release of DnaC from the DnaB⅐DnaC complex to allow DnaB to be activated. A similar mechanism has been noted for DnaG primase, in which binding of DnaG stimulates DnaC release from DnaB⅐DnaC (34).…”

Section: Discussionsupporting

confidence: 62%

Structure and Function of the PriC DNA Replication Restart Protein

Wessel

Cornilescu

et al. 2016

Journal of Biological Chemistry

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Collisions between DNA replication complexes (replisomes) and barriers such as damaged DNA or tightly bound protein complexes can dissociate replisomes from chromosomes prematurely. Replisomes must be reloaded under these circumstances to avoid incomplete replication and cell death. Bacteria have evolved multiple pathways that initiate DNA replication restart by recognizing and remodeling abandoned replication forks and reloading the replicative helicase. In vitro, the simplest of these pathways is mediated by the single-domain PriC protein, which, along with the DnaC helicase loader, can load the DnaB replicative helicase onto DNA bound by the singlestranded DNA (ssDNA)-binding protein (SSB). Previous biochemical studies have identified PriC residues that mediate interactions with ssDNA and SSB. However, the mechanisms by which PriC drives DNA replication restart have remained poorly defined due to the limited structural information available for PriC. Here, we report the NMR structure of full-length PriC from Cronobacter sakazakii. PriC forms a compact bundle of ␣-helices that brings together residues involved in ssDNA and SSB binding at adjacent sites on the protein surface. Disruption of these interaction sites and of other conserved residues leads to decreased DnaB helicase loading onto SSB-bound DNA. We also demonstrate that PriC can directly interact with DnaB and the DnaB⅐DnaC complex. These data lead to a model in which PriC acts as a scaffold for recruiting DnaB⅐DnaC to SSB/ssDNA sites present at stalled replication forks.Replication of circular chromosomes found in many bacteria is initiated by sequence-specific binding of the DnaA initiator protein to the origin of replication, oriC, which promotes duplex DNA melting (1-4). Single-stranded DNA (ssDNA) 4 exposed by DnaA unwinding is rapidly bound by the ssDNAbinding protein (SSB). DnaA, along with the helicase loader DnaC, then directs loading of the replicative helicase, DnaB, onto the SSB-coated ssDNA (4 -7). The remaining replication proteins are recruited through protein interactions to form the full replication complex, termed the replisome (8 -12). With each round of replication, two replisomes are loaded at oriC to replicate bidirectionally around the chromosome until converging at the terminator region (13).Replisomes assembled at oriC frequently encounter physical barriers, such as damaged DNA or genome-bound protein complexes (e.g. transcription machinery), that can stall and/or prematurely dissociate the replisome from the DNA template (14). Estimates from studies in Escherichia coli suggest that very few replisomes translocate to the replication terminus without dissociating at least once during each replication cycle (15). Because unrepaired premature termination events lead to incomplete replication, genome instability, and cell death, DNA replication restart mechanisms that reload replisomes onto abandoned replication forks are essential in bacteria (16). Due to the sporadic nature of replication failure, DNA replication restart pathway...

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Section: Discussionsupporting

confidence: 62%

Structure and Function of the PriC DNA Replication Restart Protein

Wessel

Cornilescu

et al. 2016

Journal of Biological Chemistry

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“…Thus, in eukaryotic systems, it is generally thought that disruption of the helicase abolishes the ability of the fork to resume replication. A similar mechanism of helicase loading and activation regulates replisome assembly and initiation at origins in prokaryotes (58,62). The observed retention of the helicase at UV-arrested replication forks suggests a mechanism by which the replication fork may retain licensing to resume replication.…”

Section: Discussionmentioning

confidence: 95%

Fate of the replisome following arrest by UV-induced DNA damage in Escherichia coli

Jeiranian

Schalow

Courcelle

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Accurate replication in the presence of DNA damage is essential to genome stability and viability in all cells. In Escherichia coli, DNA replication forks blocked by UV-induced damage undergo a partial resection and RecF-catalyzed regression before synthesis resumes. These processing events generate distinct structural intermediates on the DNA that can be visualized in vivo using 2D agarose gels. However, the fate and behavior of the stalled replisome remains a central uncharacterized question. Here, we use thermosensitive mutants to show that the replisome's polymerases uncouple and transiently dissociate from the DNA in vivo. Inactivation of α, β, or τ subunits within the replisome is sufficient to signal and induce the RecF-mediated processing events observed following UV damage. By contrast, the helicase-primase complex (DnaB and DnaG) remains critically associated with the fork, leading to a loss of fork integrity, degradation, and aberrant intermediates when disrupted. The results reveal a dynamic replisome, capable of partial disassembly to allow access to the obstruction, while retaining subunits that maintain fork licensing and direct reassembly to the appropriate location after processing has occurred.replication fork processing | RecF pathway

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“…The interaction of the primase with DnaB and the use of these primers trigger the release of DnaC. This action defines discrete events in the transition from initiation to the elongation phase of DNA replication (Makowska-Grzyska & Kaguni, 2010).…”

Section: Additional Components Of the Orisomementioning

confidence: 99%