Cobalt and nickel impair DNA metabolism by the oxidative stress independent pathway

Metallomics ◽  
2017 ◽  
Vol 9 (11) ◽  
pp. 1596-1609 ◽  
Author(s):  
Vineet Kumar ◽  
Rajesh Kumar Mishra ◽  
Gursharan Kaur ◽  
Dipak Dutta
Keyword(s):  
Oxidative Stress ◽  
Metal Ions ◽  
Replication Fork ◽  
Double Strand Breaks ◽  
Dna Metabolism ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Replication Fork Progression ◽  
Nickel Exposure ◽  
Cobalt And Nickel

Cobalt and nickel exposure leads to DNA double-strand breaks, decelerating replication fork progression. In parallel, the metal ions inhibit RecBCD function to block SOS-mediated repair of the damaged DNA.

scholarly journals Defective Ribonucleoside Diphosphate Reductase Impairs Replication Fork Progression in Escherichia coli

2007 ◽  
Vol 189 (9) ◽  
pp. 3496-3501 ◽  
Author(s):  
Estrella Guarino ◽  
Alfonso Jiménez-Sánchez ◽  
Elena C. Guzmán
Keyword(s):  
Replication Fork ◽  
Double Strand Breaks ◽  
Permissive Temperature ◽  
Replication Forks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Replication Fork Progression ◽  
Holliday Junction Resolvase ◽  
Ribonucleoside Diphosphate Reductase ◽  
Stalled Replication Forks

ABSTRACT The observed lengthening of the C period in the presence of a defective ribonucleoside diphosphate reductase has been assumed to be due solely to the low deoxyribonucleotide supply in the nrdA101 mutant strain. We show here that the nrdA101 mutation induces DNA double-strand breaks at the permissive temperature in a recB-deficient background, suggesting an increase in the number of stalled replication forks that could account for the slowing of replication fork progression observed in the nrdA101 strain in a Rec+ context. These DNA double-strand breaks require the presence of the Holliday junction resolvase RuvABC, indicating that they have been generated from stalled replication forks that were processed by the specific reaction named “replication fork reversal.” Viability results supported the occurrence of this process, as specific lethality was observed in the nrdA101 recB double mutant and was suppressed by the additional inactivation of ruvABC. None of these effects seem to be due to the limitation of the deoxyribonucleotide supply in the nrdA101 strain even at the permissive temperature, as we found the same level of DNA double-strand breaks in the nrdA + strain growing under limited (2-μg/ml) or under optimal (5-μg/ml) thymidine concentrations. We propose that the presence of an altered NDP reductase, as a component of the replication machinery, impairs the progression of the replication fork, contributing to the lengthening of the C period in the nrdA101 mutant at the permissive temperature.

Reduced DNA double strand breaks in chlorambucil resistant cells are related to high DNA-PKcs activity and low oxidative stress

Toxicology ◽  
2003 ◽  
Vol 193 (1-2) ◽  
pp. 137-152 ◽  
Author(s):  
Istvan Boldogh ◽  
Gargi Roy ◽  
Myung-Soog Lee ◽  
Attila Bacsi ◽  
Tapas K Hazra ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Resistant Cells

scholarly journals RecO impedes RecG-SSB binding to impair the strand annealing recombination pathway in E.coli

2019 ◽  
Author(s):  
Xuefeng Pan ◽  
Li Yang ◽  
Nan Jiang ◽  
Xifang Chen ◽  
Bo Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Dna Replication ◽  
Replication Fork ◽  
Double Strand Breaks ◽  
Recombinational Repair ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Homologous Recombinational Repair ◽  
Differential Binding

AbstractFaithful duplication of genomic DNA relies not only on the fidelity of DNA replication itself, but also on fully functional DNA repair and homologous recombination machinery. We report a molecular mechanism responsible for deciding homologous recombinational repair pathways during replication dictated by binding of RecO and RecG to SSB in E.coli. Using a RecG-yfp fusion protein, we found that RecG-yfp foci appeared only in the ΔrecG, ΔrecO and ΔrecA, ΔrecO double mutants. Surprisingly, foci were not observed in wild-type ΔrecG, or double mutants where recG and either recF or, separately recR were deleted. In addition, formation of RecG-yfp foci in the ΔrecO::kanR required wildtype ssb, as ssb-113 could not substitute. This suggests that RecG and RecO binding to SSB is competitive. We also found that the UV resistance of recO alone mutant increased to certain extent by supplementing RecG. In an ssb-113 mutant, RecO and RecG worked following a different pattern. Both RecO and RecG were able to participate in repairing UV damages when grown at permissive temperature, while they could also be involved in making DNA double strand breaks when grown at nonpermissive temperature. So, our results suggested that differential binding of RecG and RecO to SSB in a DNA replication fork in Escherichia coli.may be involved in determining whether the SDSA or DSBR pathway of homologous recombinational repair is used.Author summarySingle strand DNA binding proteins (SSB) stabilize DNA holoenzyme and prevent single strand DNA from folding into non-B DNA structures in a DNA replication fork. It has also been revealed that SSB can also act as a platform for some proteins working in DNA repair and recombination to access DNA molecules when DNA replication fork needs to be reestablished. In Escherichia coli, several proteins working primarily in DNA repair and recombination were found to participate in DNA replication fork resumption by physically interacting with SSB, including RecO and RecG etc. However the hierarchy of these proteins interacting with SSB in Escherichia coli has not been well defined. In this study, we demonstrated a differential binding of RecO and RecG to SSB in DNA replication was used to establish a RecO-dependent pathway of replication fork repair by abolishing a RecG-dependent replication fork repair. We also show that, RecG and RecO could randomly participate in DNA replication repair in the absence of a functional SSB, which may be responsible for the generation of DNA double strand breaks in an ssb-113 mutant in Escherichia coli.

The Oncogene MYC Triggers Replicative Stress and DNA Damage In Multiple Myeloma

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3114-3114
Author(s):  
Francesca Cottini ◽  
Teru Hideshima ◽  
Giovanni Tonon ◽  
Kenneth C. Anderson
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Dna Replication ◽  
Plasma Cells ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Replicative Stress ◽  
Stress Markers ◽  
Dna Replication Stress

Abstract Multiple myeloma (MM) is a clonal proliferation of malignant plasma cells, carrying abnormal karyotypes, chromosomal translocations, and innumerous DNA copy-number variations. We and others have previously shown that MM cells have constitutive DNA damage and DNA damage response (DDR), while normal plasma cells (NPCs) are negative for these DDR markers. Moreover, we recently observed that markers of replicative stress, such as p-ATR and p-CHK1 together with RPA foci, are also present in MM cells. The MYC (or c-MYC) oncogene is pervasively altered in MM. Since MYC is associated with DNA replication stress, oxidative stress, and DDR, we explored whether MYC is implicated in these pathways in MM. Indeed, by analyzing various DNA damage gene expression signatures, we found a positive correlation between MYC levels and ongoing DNA damage. We next examined whether MYC modulation could alter replicative stress markers, and induce DNA double-strand breaks. In a gain-of-function model, c-MYC was expressed in U266 MM cell line, which has low c-MYC levels and importantly shows low levels of ongoing DNA damage. In parallel, the H929 and MM.1S MM cell lines were used to knock-down c-MYC expression. Re-expression of a functional MYC-EGFP in U266 cells induced replicative stress markers, such as RAD51, RPA, and phospho-CHK1 foci, as well as increased RAD51, RPA and phospho-CHK1 protein levels. To determine whether this phenotype was linked to concomitant oxidative stress, we incubated MM cells with an antioxidant reagent N-Acetylcysteine (NAC). We observed a modest reduction in replicative markers after NAC treatment, which was more evident by MYC overexpression. Taken together, these results suggest that the replicative stress induced by MYC is, at least in part, associated with oxidative stress. Additionally, MYC-EGFP positive U266 cells also show DNA damage, evidenced by appearance of phospho-H2A.X foci (which detect DNA double strand breaks), that in turn triggers an intense DNA damage response, assessed by phospho-ATM/phospho CHK2 positivity. In contrast, all these DDR markers were downregulated by MYC silencing, prior to cell death, in MM.1S and H929 MM cell lines. Finally, we examined whether targeting the replicative stress response may represent a novel therapeutic strategy in MM cells with high expression of MYC. Specifically, we treated U266 cells transduced with MYC or control LACZ cells, as well as MM.1S and H929 transfected with a specific MYC-shRNA or their scrambled shRNA controls, with a small molecule ATR inhibitor VE-821 which prevents proper DNA repair after DNA damage. Cells overexpressing MYC were significantly more sensitive to VE-821 treatment compared to controls; conversely MYC-silenced cells were more resistant to VE-821. These results suggest the potential utility of VE-821 as a novel therapeutic agent in cells with high expression of MYC. In conclusion, our data show that MYC may exert its oncogenic activity partly through its ability to trigger DNA replication stress, leading to DNA damage and genomic instability in MM cells. Given the pervasive deregulation of MYC present in MM cells, its role in DNA replication and DNA damage may correlate with the extensive genomic rearrangements observed in MM cells. Therefore, treatment strategies targeting this Achilles' heel may improve patient outcome in MM. Disclosures: Hideshima: Acetylon Pharmaceuticals: Consultancy. Anderson:Acetylon, Oncopep: Scientific Founder, Scientific Founder Other; Celgene, Millennium, BMS, Onyx: Membership on an entity's Board of Directors or advisory committees.

scholarly journals DNA Ligase IV Prevents Replication Fork Stalling and Promotes Cellular Proliferation in Triple Negative Breast Cancer

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Rashmi R. Joshi ◽  
Sk Imran Ali ◽  
Amanda K. Ashley
Keyword(s):  
Breast Cancer ◽  
Dna Damage ◽  
Replication Fork ◽  
Triple Negative ◽  
Double Strand Breaks ◽  
Dna Ligase ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Ligase Iv ◽  
Fork Stalling

DNA damage is a hallmark of cancer, and mutation and misregulation of proteins that maintain genomic fidelity are associated with the development of multiple cancers. DNA double strand breaks are arguably considered the most deleterious type of DNA damage. The nonhomologous end-joining (NHEJ) pathway is one mechanism to repair DNA double strand breaks, and proteins involved in NHEJ may also regulate DNA replication. We previously established that DNA-PKcs, a NHEJ protein, promotes genomic stability and cell viability following cellular exposure to replication stress; we wanted to discern whether another NHEJ protein, DNA ligase IV (Lig4), shares this phenotype. Our investigations focused on triple negative breast cancer cells, as, compared to nonbasal breast cancer, LIG4 is frequently amplified, and an increased gene dose is associated with higher Lig4 expression. We depleted Lig4 using siRNA and confirmed our knockdown by qPCR and western blotting. Cell survival diminished with Lig4 depletion alone, and this was associated with increased replication fork stalling. Checkpoint protein Chk1 activation and dephosphorylation were unchanged in Lig4-depleted cells. Lig4 depletion resulted in sustained DNA-PKcs phosphorylation following hydroxyurea exposure. Understanding the effect of Lig4 on genomic replication and the replication stress response will clarify the biological ramifications of inhibiting Lig4 activity. In addition, Lig4 is an attractive clinical target for directing CRISPR/Cas9-mediated repair towards homology-directed repair and away from NHEJ, thus understanding of how diminishing Lig4 impacts cell biology is critical.

scholarly journals Interstitial telomere sequences disrupt break-induced replication and drive formation of ectopic telomeres

2020 ◽  
Vol 48 (22) ◽  
pp. 12697-12710
Author(s):  
Elizabeth A Stivison ◽  
Kati J Young ◽  
Lorraine S Symington
Keyword(s):  
Replication Fork ◽  
Double Strand Breaks ◽  
Replication Forks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Homology Directed Repair ◽  
Telomere Sequence ◽  
D Loop ◽  
Break Induced Replication ◽  
Telomeric Protein

Abstract Break-induced replication (BIR) is a mechanism used to heal one-ended DNA double-strand breaks, such as those formed at collapsed replication forks or eroded telomeres. Instead of utilizing a canonical replication fork, BIR is driven by a migrating D-loop and is associated with a high frequency of mutagenesis. Here we show that when BIR encounters an interstitial telomere sequence (ITS), the machinery frequently terminates, resulting in the formation of an ectopic telomere. The primary mechanism to convert the ITS to a functional telomere is by telomerase-catalyzed addition of telomeric repeats with homology-directed repair serving as a back-up mechanism. Termination of BIR and creation of an ectopic telomere is promoted by Mph1/FANCM helicase, which has the capacity to disassemble D-loops. Other sequences that have the potential to seed new telomeres but lack the unique features of a natural telomere sequence, do not terminate BIR at a significant frequency in wild-type cells. However, these sequences can form ectopic telomeres if BIR is made less processive. Our results support a model in which features of the ITS itself, such as the propensity to form secondary structures and telomeric protein binding, pose a challenge to BIR and increase the vulnerability of the D-loop to dissociation by helicases, thereby promoting ectopic telomere formation.

scholarly journals HMCES Maintains Replication Fork Progression and Prevents Double-Strand Breaks in Response to APOBEC Deamination and Abasic Site Formation

Cell Reports ◽  
2020 ◽  
Vol 31 (9) ◽  
pp. 107705 ◽  
Author(s):  
Kavi P.M. Mehta ◽  
Courtney A. Lovejoy ◽  
Runxiang Zhao ◽  
Darren R. Heintzman ◽  
David Cortez
Keyword(s):  
Replication Fork ◽  
Double Strand Breaks ◽  
Site Formation ◽  
Abasic Site ◽  
Strand Breaks ◽  
Replication Fork Progression

scholarly journals qDSB-Seq: quantitative DNA double-strand break sequencing

2017 ◽  
Author(s):  
Yingjie Zhu ◽  
Anna Biernacka ◽  
Benjamin Pardo ◽  
Norbert Dojer ◽  
Romain Forey ◽  
...  
Keyword(s):  
Replication Fork ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Site Specific ◽  
Strand Breaks ◽  
Dna Double Strand Break ◽  
Physiological Relevance ◽  
A Site ◽  
First Time

AbstractSequencing-based methods for mapping DNA double-strand breaks (DSBs) allow measurement only of relative frequencies of DSBs between loci, which limits our understanding of the physiological relevance of detected DSBs. We propose quantitative DSB sequencing (qDSB-Seq), a method providing both DSB frequencies per cell and their precise genomic coordinates. We induced spike-in DSBs by a site-specific endonuclease and used them to quantify labeled DSBs (e.g. using i-BLESS). Utilizing qDSB-Seq, we determined numbers of DSBs induced by a radiomimetic drug and various forms of replication stress, and revealed several orders of magnitude differences in DSB frequencies. We also measured for the first time Top1-dependent absolute DSB frequencies at replication fork barriers. qDSB-Seq is compatible with various DSB labeling methods in different organisms and allows accurate comparisons of absolute DSB frequencies across samples.

scholarly journals Triplex structures induce DNA double strand breaks via replication fork collapse in NER deficient cells

2016 ◽  
Vol 44 (16) ◽  
pp. 7742-7754 ◽  
Author(s):  
Meetu Kaushik Tiwari ◽  
Nneoma Adaku ◽  
Natoya Peart ◽  
Faye A. Rogers
Keyword(s):  
Replication Fork ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks

scholarly journals Role of Interleukin33 in Rejuvenation of Aged Neurons and Age-Related Dementias

2021 ◽  
Vol 16 ◽  
pp. 263310552110302
Author(s):  
Yahuan Lou
Keyword(s):  
Oxidative Stress ◽  
Potential Risk ◽  
Middle Age ◽  
Late Onset ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Age Related ◽  
Deficient Mice

Late-onset Alzheimer’s disease (LOAD) is the most common age-related dementia, and its etiology remains unclear. Recent studies have linked abnormal neuronal aging to LOAD. Neurons are non-proliferative, and thus, majority of aged neurons must be rejuvenated through repairing or eliminating damaged molecules to regain their healthy status and functionalities. We discovered a surge of oxidative stress in neurons at middle age in mice. A rapid upregulation of neuronal rejuvenation is vital, while astrocyte-expressed interleukin33 (IL33), an IL1-like cytokine, is critical for this process. Thus, IL33-deficiency cripples the neuronal rejuvenation mechanisms, such as repairing DNA double strand breaks, eliminating damaged molecules by autophagy or by glymphatic drainage. IL33-deficient mice develop tau deposition and age-related dementia following a path similar to LOAD. We hypothesize that any interferences on IL33-initiated rejuvenation process for aged neurons after middle life is a potential risk for LOAD development.

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