Oxidation of the Guanine Nucleotide Pool Underlies Cell Death by Bactericidal Antibiotics

Foti, James J.; Devadoss, Babho; Winkler, Julian; Collins, James J.; Walker, Graham C.

doi:10.1126/science.1219192

Cited by 436 publications

(492 citation statements)

References 47 publications

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“…Some of these stresses have been reported to result in the production of oxygen radicals or a mutator phenotype (38,39,42,44). In this light, it is relevant to ask whether the A301V and G295S mutants may also suffer from stress and whether their poor growth and hypermutator phenotype could result, at least in part, from such alternative disturbances.…”

Section: Discussionmentioning

confidence: 99%

“…Since the first described cases of MMR saturation and error catastrophe (20,22), new insight has emerged into the physiology of stressed bacteria, including stress due to carbon source deprivation (37), antibiotic exposure (38)(39)(40), impaired replication fork progress (38,41), and dNTP pool depletion by the RNR inhibitor, hydroxyurea (42,43). Some of these stresses have been reported to result in the production of oxygen radicals or a mutator phenotype (38,39,42,44).…”

Section: Discussionmentioning

confidence: 99%

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Hypermutability and error catastrophe due to defects in ribonucleotide reductase

Ahluwalia

Schaaper

2013

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

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The enzyme ribonucleotide reductase (RNR) plays a critical role in the production of deoxynucleoside-5′-triphosphates (dNTPs), the building blocks for DNA synthesis and replication. The levels of the cellular dNTPs are tightly controlled, in large part through allosteric control of RNR. One important reason for controlling the dNTPs relates to their ability to affect the fidelity of DNA replication and, hence, the cellular mutation rate. We have previously isolated a set of mutants of Escherichia coli RNR that are characterized by altered dNTP pools and increased mutation rates (mutator mutants). Here, we show that one particular set of RNR mutants, carrying alterations at the enzyme's allosteric specificity site, is characterized by relatively modest dNTP pool deviations but exceptionally strong mutator phenotypes, when measured in a mutational forward assay (>1,000-fold increases). We provide evidence indicating that this high mutability is due to a saturation of the DNA mismatch repair system, leading to hypermutability and error catastrophe. The results indicate that, surprisingly, even modest deviations of the cellular dNTP pools, particularly when the pool deviations promote particular types of replication errors, can have dramatic consequences for mutation rates.T he enzyme ribonucleotide reductase (RNR) is a critical cellular factor for the synthesis and control of the deoxynucleoside-5′-triphosphates (dNTPs), the building blocks for DNA replication and DNA repair (1). Specifically, RNR is responsible for the reduction of the ribonucleotides to the corresponding deoxynucleotides. In many well-studied cell systems, like the bacterium Escherichia coli, the yeast Saccharomyces cerevisiae, or mammalian cells, this reduction takes place at the level of the nucleoside diphosphates (NDP → dNDP), and each of four separate NDPs (ADP, GDP, CDP, and UDP) can serve as RNR substrate (1, 2). Following reduction, the dNDPs are converted to the corresponding dNTPs by nucleoside diphosphate kinase (NDK) (3). The DNA precursor dTTP is not generated directly through this pathway; instead, it is produced from dCTP via dUTP (4).RNRs have been subdivided into several classes, depending on the type of radical used in the catalytic reaction (1, 5-7). The class Ia RNR, as present in E. coli, yeast, and mammalian cells, employs a tyrosyl radical. Structurally, these RNRs are tetramers composed of a dimer of a large subunit (R1) and a dimer of a small subunit (R2). The large subunits contain the catalytic site and two allosteric regulatory sites (termed specificity site and activity site), whereas the small subunit contains the essential tyrosyl radical. The activity site is located at the N terminus of the R1 subunit and functions as an "on-off" switch: ATP binding leads to an active enzyme, whereas dATP binding inhibits the enzyme. Hence, by monitoring the ATP/dATP ratio, the enzyme aims to ensure an overall dNTP level that is presumably optimal for DNA replication (1, 8).The R1 specificity site, is a binding site for dATP, ATP,...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Hypermutability and error catastrophe due to defects in ribonucleotide reductase

Ahluwalia

Schaaper

2013

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

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“…17 Intriguingly, pol IV has also been shown to incorporate 8-oxo-dGTP, which occurs as a result of oxidation of the guanine nucleotide pool, such as following exposure to antibiotics. 18 This activity of pol IV appears to potentiate cell death during antibiotic treatment, presumably due to a high frequency of DSBs caused by incomplete repair of closely spaced 8-oxo-dGMP lesions. 18 Considering that the RpoS response upregulates pol IV by ~100% and promotes resistance to oxidation, the ability of pol IV to incorporate 8-oxo-dGTP may also be beneficial for survival.…”

Section: Introductionmentioning

confidence: 99%

“…18 This activity of pol IV appears to potentiate cell death during antibiotic treatment, presumably due to a high frequency of DSBs caused by incomplete repair of closely spaced 8-oxo-dGMP lesions. 18 Considering that the RpoS response upregulates pol IV by ~100% and promotes resistance to oxidation, the ability of pol IV to incorporate 8-oxo-dGTP may also be beneficial for survival. 19,20 Although the mode of replication in which pol IV incorporates 8-oxo-dGTP has yet to be elucidated, the suggested high frequency of 8-oxo-dGTP incorporation during antibiotic treatment indicates that pol IV is actively engaged in replication during stress, which may be accounted for by pol IV RDR activity.…”

Section: Introductionmentioning

confidence: 99%

“…19,20 Although the mode of replication in which pol IV incorporates 8-oxo-dGTP has yet to be elucidated, the suggested high frequency of 8-oxo-dGTP incorporation during antibiotic treatment indicates that pol IV is actively engaged in replication during stress, which may be accounted for by pol IV RDR activity. 18 Taken together, pol IV was probably selected to perform multiple functions in DNA damage tolerance in stressed cells, including RDR, TLS, and 8-oxo-dGMP incorporation.…”

Section: Introductionmentioning

confidence: 99%

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DNA polymerases are error-prone at RecA-mediated recombination intermediates

2013

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G enetic studies have suggested thatY-family translesion DNA polymerase IV (DinB) performs error-prone recombination-directed replication (RDR) under conditions of stress due to its ability to promote mutations during double-strand break (DSB) repair in growth-limited E. coli cells. In recent studies we have demonstrated that pol IV is preferentially recruited to D-loop recombination intermediates at stressinduced concentrations and is highly mutagenic during RDR in vitro. These findings verify longstanding genetic data that have implicated pol IV in promoting stress-induced mutagenesis at D-loops. In this Extra View, we demonstrate the surprising finding that A-family pol I, which normally exhibits high-fidelity DNA synthesis, is highly error-prone at D-loops like pol IV. These findings indicate that DNA polymerases are intrinsically error-prone at RecA-mediated D-loops and suggest that auxiliary factors are necessary for suppressing mutations during RDR in non-stressed proliferating cells.

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