Role of PriA in Replication Fork Reactivation in
            <i>Escherichia coli</i>

Sandler, Steven J.; Marians, Kenneth J.

doi:10.1128/jb.182.1.9-13.2000

Cited by 204 publications

(178 citation statements)

References 57 publications

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“…1, step D; the same reaction can occur in RecA ϩ cells if RecBCD encounters the HJ before a chi site). Because PriA recognizes both D loops formed by homologous recombination and fork structures (2), it promotes the reassembly of a functional replisome regardless of whether the DNA doublestrand end is recombined into its homologous sister sequence or degraded (21). In the absence of RecBC, resolution of the HJ by RuvABC causes chromosome linearization (Fig.…”

Section: Replication Mutants and Replication Fork Reversalmentioning

confidence: 99%

“…16 and 17). The key enzyme for replication restart is PriA, which, in combination with other proteins, promotes the loading of the replicative helicase DnaB and in turn the assembly of a functional replisome (2). PriA allows replication to initiate from a recombination intermediate, possibly because, as described below, recombination intermediates can be generated from replication forks.…”

Section: Dna Double-strand End Repair In Bacteriamentioning

confidence: 99%

“…Because RecA-dependent fork reversal in the dnaBts mutant did not require RecFOR, there has to be an alternative pathway for SSB removal (24). During replication restart, SSB is displaced from the lagging-strand template by PriA and its associated partners (the preprimosome proteins) in a reaction concerted with the loading of the DnaB helicase (2). We can speculate that in a dnaBts mutant, the preprimosome proteins displace SSB from the lagging-strand template without being able to replace it with a functional DnaB helicase and thereby provide SSB-free ssDNA, accessible to RecA.…”

Section: Reca-mediated Replication Fork Reversal In the Dnabts Mutantmentioning

confidence: 99%

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Multiple pathways process stalled replication forks

Michel

Grompone

Flores

et al. 2004

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

309

330

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Impairment of replication fork progression is a serious threat to living organisms and a potential source of genome instability. Studies in prokaryotes have provided evidence that inactivated replication forks can restart by the reassembly of the replication machinery. Several strategies for the processing of inactivated replication forks before replisome reassembly have been described. Most of these require the action of recombination proteins, with different proteins being implicated, depending on the cause of fork arrest. The action of recombination proteins at blocked forks is not necessarily accompanied by a strand-exchange reaction and may prevent rather than repair fork breakage. These various restart pathways may reflect different structures at stalled forks. We review here the different strategies of fork processing elicited by different kinds of replication impairments in prokaryotes and the variety of roles played by recombination proteins in these processes.W ork from several laboratories has established that in bacteria, a recombination event can lead to the establishment of a unidirectional replication fork (reviewed in refs. 1-3). These observations extend the concept of a direct recombination-replication connection, originally proposed Ϸ30 years ago from studies of bacteriophage T4 and replication. Furthermore, the existence of recombination-dependent replication in yeast suggests that this connection may be a widely distributed phenomenon (4, 5).Considering the tight control of replication initiation at chromosomal origins, the assembly of a complete replisome at recombination intermediates, independently of time and place, is paradoxical. One of the raisons d'être of this potentially dangerous process was revealed by the finding that recombination intermediates form at inactivated replication forks and are used for replication restart. However, studies of the replicationrecombination connection in Escherichia coli have indicated that recombination proteins do not necessarily catalyze strand exchange at blocked forks and rather act in a variety of reactions that depend on the origin of the arrest. We review here the diversity of fates of inactivated replication forks in bacteria, as well as our present knowledge of the roles played by recombination proteins during replication restart. DNA Double-Strand End Repair in BacteriaAlmost 30 years ago, Higgins et al. (6) proposed that blocked replication forks could be isomerized into a four-way Holliday junction (HJ) with a DNA double-strand end, which could permit DNA repair and then continuation of replication (Fig. 1, step A). The test of the model, performed by treatment of mammalian cells with a DNA-damaging agent, was inconclusive (7). However, more recent studies in E. coli suggest that such replication fork reversal plays a crucial role in replication restart in bacteria (8,9).A key aspect of the replication fork reversal model is that it generates a DNA double-strand end at blocked forks without chromosome breakage. In E. coli, the enzyme th...

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Section: Replication Mutants and Replication Fork Reversalmentioning

confidence: 99%

Section: Dna Double-strand End Repair In Bacteriamentioning

confidence: 99%

Section: Reca-mediated Replication Fork Reversal In the Dnabts Mutantmentioning

confidence: 99%

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Multiple pathways process stalled replication forks

Michel

Grompone

Flores

et al. 2004

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

309

330

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“…Yet polymerase complexes assembled at origins of replication often fail to complete the task (1). Despite the intrinsic processivity of these complexes, the advance of replication forks is hindered by lesions or troublesome sequences in the template DNA and by protein complexes associated with gene expression and DNA packaging (2)(3)(4).…”

mentioning

confidence: 99%

Rescue of stalled replication forks by RecG: Simultaneous translocation on the leading and lagging strand templates supports an active DNA unwinding model of fork reversal and Holliday junction formation

McGlynn

Lloyd

2001

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

173

192

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Modification of damaged replication forks is emerging as a crucial factor for efficient chromosomal duplication and the avoidance of genetic instability. The RecG helicase of Escherichia coli, which is involved in recombination and DNA repair, has been postulated to act on stalled replication forks to promote replication restart via the formation of a four-stranded (Holliday) junction. Here we show that RecG can actively unwind the leading and lagging strand arms of model replication fork structures in vitro. Unwinding is achieved in each case by simultaneous interaction with and translocation along both the leading and lagging strand templates at a fork. Disruption of either of these interactions dramatically inhibits unwinding of the opposing duplex arm. Thus, RecG translocates simultaneously along two DNA strands, one with 5 -3 and the other with 3 -5 polarity. The unwinding of both nascent strands at a damaged fork, and their subsequent annealing to form a Holliday junction, may explain the ability of RecG to promote replication restart. Moreover, the preferential binding of partial forks lacking a leading strand suggests that RecG may have the ability to target stalled replication intermediates in vivo in which lagging strand synthesis has continued beyond the leading strand.DNA repair ͉ recombination ͉ helicases

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“…Escherichia coli X-type primosome was originally discovered as an essential component for the replication of bacteriophage X174 and ColE1-type plasmids (3,4). It is now clear that the primary role of the X-type primosome is to restart the stalled replication fork at oriC after encountering DNA damage (5)(6)(7)(8). During replication restart, in vitro evidence suggests that the X-type primosome is located at the D-loop, a threeway-junction DNA structure that is an intermediate in recombination repair, and that PriA initiates the primosome assembly at the D-loop (9 -12).…”

mentioning

confidence: 99%

Crystal Structure of PriB, a Primosomal DNA Replication Protein of Escherichia coli

Liu

Chang²,

Huang

et al. 2004

Journal of Biological Chemistry

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PriB is one of the Escherichia coli X-type primosome proteins that are required for assembly of the primosome, a mobile multi-enzyme complex responsible for the initiation of DNA replication. Here we report the crystal structure of the E. coli PriB at 2.1 Å resolution by multi-wavelength anomalous diffraction using a mercury derivative. The polypeptide chain of PriB is structurally similar to that of single-stranded DNA-binding protein (SSB). However, the biological unit of PriB is a dimer, not a homotetramer like SSB. Electrophoretic mobility shift assays demonstrated that PriB binds single-stranded DNA and single-stranded RNA with comparable affinity. We also show that PriB binds singlestranded DNA with certain base preferences. Based on the PriB structural information and biochemical studies, we propose that the potential tetramer formation surface and several other regions of PriB may participate in protein-protein interaction during DNA replication. These findings may illuminate the role of PriB in X-type primosome assembly.

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Role of PriA in Replication Fork Reactivation in Escherichia coli

Cited by 204 publications

References 57 publications

Multiple pathways process stalled replication forks

Multiple pathways process stalled replication forks

Rescue of stalled replication forks by RecG: Simultaneous translocation on the leading and lagging strand templates supports an active DNA unwinding model of fork reversal and Holliday junction formation

Crystal Structure of PriB, a Primosomal DNA Replication Protein of Escherichia coli

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