Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 115, Issue 9, Pages 2210-2215Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1719627115
Keywords
DNA double-strand breaks; 5-OH-dCTP; reactive oxygen species; antibiotic; Mycobacterium
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Funding
- Chinese National Mega Science and Technology Program [2017ZX10301301-001]
- National Natural Science Foundation [31430004, 31771004]
- Research Unit Fund of Li Ka Shing Institute of Health Sciences [7103506]
- Shanghai Science and Technology Commission [17ZR1423900]
- Fudan University
- Scientific Research Innovation Team Project of Anhui Colleges and Universities [2016-40]
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Growing evidence shows that generation of reactive oxygen species (ROS) derived from antibiotic-induced metabolic perturbation contribute to antibiotic lethality. However, our knowledge of the mechanisms by which antibiotic-induced oxidative stress actually kills cells remains elusive. Here, we show that oxidation of dCTP underlies ROS-mediated antibiotic lethality via induction of DNA double-strand breaks (DSBs). Deletion of mazG-encoded 5-OH-dCTP-specific pyrophosphohydrolase potentiates antibiotic killing of stationary-phase mycobacteria, but did not affect antibiotic efficacy in exponentially growing cultures. Critically, the effect of mazG deletion on potentiating antibiotic killing is associated with antibiotic-induced ROS and accumulation of 5-OH-dCTP. Independent lines of evidence presented here indicate that the increased level of DSBs observed in the Delta mazG mutant is a dead-end event accounting for enhanced antibiotic killing. Moreover, we provided genetic evidence that 5-OH-dCTP is incorporated into genomic DNA via error-prone DNA polymerase DnaE2 and repair of 5-OH-dC lesions via the endonuclease Nth leads to the generation of lethal DSBs. This work provides a mechanistic view of ROS-mediated antibiotic lethality in stationary phase and may have broad implications not only with respect to antibiotic lethality but also to the mechanism of stress-induced mutagenesis in bacteria.
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