The inhibition of ribonucleoside diphosphate reductase by hydroxyurea, guanazole and pyrazoloimidazole (IMPY)

Moore, E. Colleen; Hurlbert, Robert B.

doi:10.1016/0163-7258(85)90068-3

Cited by 63 publications

(6 citation statements)

References 175 publications

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“…Since both cognate DNA damage and noncognate DNA damage enrich Pol IV at the replication fork in an SSB-dependent manner, our results suggest that any obstacles to processive replication may act as a molecular signal for the recruitment of Pol IV. To test this possibility, we treated cells with the ribonucleotide reductase (RNR) inhibitor hydroxyurea (HU) ( 40 ). RNR inhibition by HU depletes cellular deoxynucleoside triphosphate pools, ultimately leading to replication stalling and cell death ( 41 ).…”

Section: Resultsmentioning

confidence: 99%

Replication stalling activates SSB for recruitment of DNA damage tolerance factors

Thrall

Piatt

Chang

et al. 2022

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

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Translesion synthesis (TLS) polymerases bypass DNA lesions that block replicative polymerases, allowing cells to tolerate DNA damage encountered during replication. It is well known that most bacterial TLS polymerases must interact with the sliding-clamp processivity factor to carry out TLS, but recent work in Escherichia coli has revealed that single-stranded DNA-binding protein (SSB) plays a key role in enriching the TLS polymerase Pol IV at stalled replication forks in the presence of DNA damage. It remains unclear how this interaction with SSB enriches Pol IV in a stalling-dependent manner given that SSB is always present at the replication fork. In this study, we use single-molecule imaging in live E. coli cells to investigate this SSB-dependent enrichment of Pol IV. We find that Pol IV is enriched through its interaction with SSB in response to a range of different replication stresses and that changes in SSB dynamics at stalled forks may explain this conditional Pol IV enrichment. Finally, we show that other SSB-interacting proteins are likewise selectively enriched in response to replication perturbations, suggesting that this mechanism is likely a general one for enrichment of repair factors near stalled replication forks.

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Section: Resultsmentioning

confidence: 99%

Replication stalling activates SSB for recruitment of DNA damage tolerance factors

Thrall

Piatt

Chang

et al. 2022

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

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“…HU inhibits the activity of RNR by scavenging its free radical necessary for catalysis, and the reduced RNR activity leads to decreased concentration of dNTPs in the cell [35]. Here, wild type cells (MG1655) grown in glu-CAA-uri medium at 37°C, were treated with different concentrations of HU (2.5, 5 and 10 mM) to see if we could obtain a situation of reduced fork movement, but unchanged growth rate.…”

Section: Resultsmentioning

confidence: 99%

A Reduction in Ribonucleotide Reductase Activity Slows Down the Chromosome Replication Fork but Does Not Change Its Localization

2009

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BackgroundIt has been proposed that the enzymes of nucleotide biosynthesis may be compartmentalized or concentrated in a structure affecting the organization of newly replicated DNA. Here we have investigated the effect of changes in ribonucleotide reductase (RNR) activity on chromosome replication and organization of replication forks in Escherichia coli.Methodology/Principal FindingsReduced concentrations of deoxyribonucleotides (dNTPs) obtained by reducing the activity of wild type RNR by treatment with hydroxyurea or by mutation, resulted in a lengthening of the replication period. The replication fork speed was found to be gradually reduced proportionately to moderate reductions in nucleotide availability. Cells with highly extended C periods showed a “delay” in cell division i.e. had a higher cell mass. Visualization of SeqA structures by immunofluorescence indicated no change in organization of the new DNA upon moderate limitation of RNR activity. Severe nucleotide limitation led to replication fork stalling and reversal. Well defined SeqA structures were not found in situations of extensive replication fork repair. In cells with stalled forks obtained by UV irradiation, considerable DNA compaction was observed, possibly indicating a reorganization of the DNA into a “repair structure” during the initial phase of the SOS response.Conclusion/SignificanceThe results indicate that the replication fork is slowed down in a controlled manner during moderate nucleotide depletion and that a change in the activity of RNR does not lead to a change in the organization of newly replicated DNA. Control of cell division but not control of initiation was affected by the changes in replication elongation.

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“…Common fragile sites are large genomic regions of 250 kb–1 Mb that are unstable under conditions that partially inhibit DNA replication (reviewed in [1]). Treatment with aphidicolin, which inhibits DNA polymerases [2], [3], or hydroxyurea, which inhibits ribonucleotide reductase and results in unbalanced nucleotide pools [4], both cause replication stress that induces instability at fragile sites. Several mechanisms have been proposed to explain why breaks form in human common fragile sites, including secondary structure formation within single-stranded DNA (ssDNA) at stalled replication forks [5], [6], paucity of replication origins [7], [8], replication fork pausing between early- and late-replicating regions [9], [10], and collision between RNA and DNA polymerases [11].…”

Section: Introductionmentioning

confidence: 99%

Fragile Site Instability in Saccharomyces cerevisiae Causes Loss of Heterozygosity by Mitotic Crossovers and Break-Induced Replication

et al. 2013

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Loss of heterozygosity (LOH) at tumor suppressor loci is a major contributor to cancer initiation and progression. Both deletions and mitotic recombination can lead to LOH. Certain chromosomal loci known as common fragile sites are susceptible to DNA lesions under replication stress, and replication stress is prevalent in early stage tumor cells. There is extensive evidence for deletions stimulated by common fragile sites in tumors, but the role of fragile sites in stimulating mitotic recombination that causes LOH is unknown. Here, we have used the yeast model system to study the relationship between fragile site instability and mitotic recombination that results in LOH. A naturally occurring fragile site, FS2, exists on the right arm of yeast chromosome III, and we have analyzed LOH on this chromosome. We report that the frequency of spontaneous mitotic BIR events resulting in LOH on the right arm of yeast chromosome III is higher than expected, and that replication stress by low levels of polymerase alpha increases mitotic recombination 12-fold. Using single-nucleotide polymorphisms between the two chromosome III homologs, we mapped the locations of recombination events and determined that FS2 is a strong hotspot for both mitotic reciprocal crossovers and break-induced replication events under conditions of replication stress.

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The inhibition of ribonucleoside diphosphate reductase by hydroxyurea, guanazole and pyrazoloimidazole (IMPY)

Cited by 63 publications

References 175 publications

Replication stalling activates SSB for recruitment of DNA damage tolerance factors

Replication stalling activates SSB for recruitment of DNA damage tolerance factors

A Reduction in Ribonucleotide Reductase Activity Slows Down the Chromosome Replication Fork but Does Not Change Its Localization

Fragile Site Instability in Saccharomyces cerevisiae Causes Loss of Heterozygosity by Mitotic Crossovers and Break-Induced Replication

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