Radiation dosimetry and repair kinetics of DNA damage foci in mouse pachytene spermatocyte and round spermatid stages

AbstractThe poly(ADP-ribose) polymerase, PARP1, plays a key role in maintaining genomic integrity by detecting DNA damage and mediating repair. γH2A.X is the primary histone marker for DNA double-strand breaks and PARP1 localizes to H2A.X-enriched chromatin damage sites, but the basis for this association is not clear. We characterize the kinetics of PARP1 binding to a variety of nucleosomes harbouring DNA double-strand breaks, which reveal that PARP1 associates faster with (γ)H2A.X- versus H2A-nucleosomes, resulting in a higher affinity for the former, which is maximal for γH2A.X-nucleosome that is also the activator eliciting the greatest poly-ADP-ribosylation catalytic efficiency. The enhanced activities with γH2A.X-nucleosome coincide with increased accessibility of the DNA termini resulting from the H2A.X-Ser139 phosphorylation. Indeed, H2A- and (γ)H2A.X-nucleosomes have distinct stability characteristics, which are rationalized by mutational analysis and (γ)H2A.X-nucleosome core crystal structures. This suggests that the γH2A.X epigenetic marker directly facilitates DNA repair by stabilizing PARP1 association and promoting catalysis.

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The poly(ADP-ribose)-dependent chromatin remodeler Alc1 induces local chromatin relaxation upon DNA damage

Molecular Biology of the Cell ◽

10.1091/mbc.e16-05-0269 ◽

2016 ◽

Vol 27 (24) ◽

pp. 3791-3799 ◽

Cited By ~ 56

Author(s):

Hafida Sellou ◽

Théo Lebeaupin ◽

Catherine Chapuis ◽

Rebecca Smith ◽

Anna Hegele ◽

...

Keyword(s):

Dna Damage ◽

Structural Changes ◽

Cellular Responses ◽

Dna Lesions ◽

Fast Kinetics ◽

Important Player ◽

Chromatin Relaxation ◽

Kinetics Of ◽

Laser Microirradiation

Chromatin relaxation is one of the earliest cellular responses to DNA damage. However, what determines these structural changes, including their ATP requirement, is not well understood. Using live-cell imaging and laser microirradiation to induce DNA lesions, we show that the local chromatin relaxation at DNA damage sites is regulated by PARP1 enzymatic activity. We also report that H1 is mobilized at DNA damage sites, but, since this mobilization is largely independent of poly(ADP-ribosyl)ation, it cannot solely explain the chromatin relaxation. Finally, we demonstrate the involvement of Alc1, a poly(ADP-ribose)- and ATP-dependent remodeler, in the chromatin-relaxation process. Deletion of Alc1 impairs chromatin relaxation after DNA damage, while its overexpression strongly enhances relaxation. Altogether our results identify Alc1 as an important player in the fast kinetics of the NAD+- and ATP-dependent chromatin relaxation upon DNA damage in vivo.

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Spatiotemporal kinetics of γ-H2AX protein on charged particles induced DNA damage

Applied Surface Science ◽

10.1016/j.apsusc.2014.03.079 ◽

2014 ◽

Vol 310 ◽

pp. 62-65 ◽

Cited By ~ 2

Author(s):

H. Niu ◽

H.C. Chang ◽

I.C. Cho ◽

C.H. Chen ◽

C.S. Liu ◽

...

Keyword(s):

Dna Damage ◽

Charged Particles ◽

Kinetics Of

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Kinetics of DNA Repair Under Chronic Irradiation at Low and Medium Dose Rates in Repair Proficient and Repair Compromised Normal Fibroblasts

Radiation Research ◽

10.1667/rade-21-00158.1 ◽

2021 ◽

Author(s):

Elena K. Zaharieva ◽

Megumi Sasatani ◽

Kenji Kamiya

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Dose Rate ◽

Dose Response ◽

Chronic Irradiation ◽

Dose Rates ◽

Chronic Radiation ◽

Damage Repair ◽

Kinetics Of ◽

Medium Dose

We present time and dose dependencies for the formation of 53BP1 and γH2AX DNA damage repair foci after chronic radiation exposure at dose rates of 140, 250 and 450 mGy/day from 3 to 96 h, in human and mouse repair proficient and ATM or DNA-PK deficient repair compromised cell models. We describe the time/dose-response curves using a mathematical equation which contains a linear component for the induction of DNA damage repair foci after irradiation, and an exponential component for their resolution. We show that under conditions of chronic irradiation at low and medium dose rates, the processes of DNA double-strand breaks (DSBs) induction and repair establish an equilibrium, which in repair proficient cells manifests as a plateau-shaped dose-response where the plateau is reached within the first 24 h postirradiation, and its height is proportionate to the radiation dose rate. In contrast, in repair compromised cells, where the rate of repair may be exceeded by the DSB induction rate, DNA damage accumulates with time of exposure and total absorbed dose. In addition, we discuss the biological meaning of the observed dependencies by presenting the frequency of micronuclei formation under the same irradiation conditions as a marker of radiation-induced genomic instability. We believe that the data and analysis presented here shed light on the kinetics of DNA repair under chronic radiation and are useful for future studies in the low-to-medium dose rate range.

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Characterization of the Two Mycobacterium tuberculosis recA Promoters

Journal of Bacteriology ◽

10.1128/jb.185.20.6005-6015.2003 ◽

2003 ◽

Vol 185 (20) ◽

pp. 6005-6015 ◽

Cited By ~ 21

Author(s):

Krishna K. Gopaul ◽

Patricia C. Brooks ◽

Jean-François Prost ◽

Elaine O. Davis

Keyword(s):

Escherichia Coli ◽

Dna Damage ◽

Mycobacterium Tuberculosis ◽

Promoter Activity ◽

The Other ◽

Expression Level ◽

Promoter Elements ◽

Kinetics Of

ABSTRACT The recA gene of Mycobacterium tuberculosis is unusual in that it is expressed from two promoters, one of which, P1, is DNA damage inducible independently of LexA and RecA, while the other, P2, is regulated by LexA in the classical way (E. O. Davis, B. Springer, K. K. Gopaul, K. G. Papavinasasundaram, P. Sander, and E. C. Böttger, Mol. Microbiol. 46:791-800, 2002). In this study we characterized these two promoters in more detail. Firstly, we localized the promoter elements for each of the promoters, and in so doing we identified a mutation in each promoter which eliminates promoter activity. Interestingly, a motif with similarity to Escherichia coli σ70 −35 elements but located much closer to the −10 element is important for optimal expression of P1, whereas the sequence at the −35 location is not. Secondly, we found that the sequences flanking the promoters can have a profound effect on the expression level directed by each of the promoters. Finally, we examined the contribution of each of the promoters to recA expression and compared their kinetics of induction following DNA damage.

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Kinetics of DNA Damage

Molecular Life Sciences ◽

10.1007/978-1-4614-1531-2_308 ◽

2018 ◽

pp. 623-624

Author(s):

Frederick Peter Guengerich

Keyword(s):

Dna Damage ◽

Kinetics Of

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Performance Evaluation for Repair of HSGc-C5 Carcinoma Cell Using Geant4-DNA

Cancers ◽

10.3390/cancers13236046 ◽

2021 ◽

Vol 13 (23) ◽

pp. 6046

Author(s):

Dousatsu Sakata ◽

Masao Suzuki ◽

Ryoichi Hirayama ◽

Yasushi Abe ◽

Masayuki Muramatsu ◽

...

Keyword(s):

Dna Damage ◽

Radiation Treatment ◽

Carcinoma Cell ◽

Carcinoma Cells ◽

Model Parameters ◽

Track Structure ◽

V79 Cells ◽

Damage Repair ◽

Kinetics Of ◽

Mev Protons

Track-structure Monte Carlo simulations are useful tools to evaluate initial DNA damage induced by irradiation. In the previous study, we have developed a Gean4-DNA-based application to estimate the cell surviving fraction of V79 cells after irradiation, bridging the gap between the initial DNA damage and the DNA rejoining kinetics by means of the two-lesion kinetics (TLK) model. However, since the DNA repair performance depends on cell line, the same model parameters cannot be used for different cell lines. Thus, we extended the Geant4-DNA application with a TLK model for the evaluation of DNA damage repair performance in HSGc-C5 carcinoma cells which are typically used for evaluating proton/carbon radiation treatment effects. For this evaluation, we also performed experimental measurements for cell surviving fractions and DNA rejoining kinetics of the HSGc-C5 cells irradiated by 70 MeV protons at the cyclotron facility at the National Institutes for Quantum and Radiological Science and Technology (QST). Concerning fast- and slow-DNA rejoining, the TLK model parameters were adequately optimized with the simulated initial DNA damage. The optimized DNA rejoining speeds were reasonably agreed with the experimental DNA rejoining speeds. Using the optimized TLK model, the Geant4-DNA simulation is now able to predict cell survival and DNA-rejoining kinetics for HSGc-C5 cells.

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