Rescue of mitomycin C- or psoralen-inactivated Micrococcus radiodurans by additional exposure to radiation or alkylating agents

1982 ◽  
Vol 152 (3) ◽  
pp. 976-982
Author(s):  
M T Hansen
Keyword(s):  
Mitomycin C ◽  
Uv Radiation ◽  
Uv Light ◽  
Alkylating Agents ◽  
Repair System ◽  
Wild Type ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
Cellular Dna ◽  
Constitutive Synthesis

The processing of damaged DNA was altered in a mitomycin C-sensitive mutant (mtcA) of Micrococcus radiodurans. Even though the mutant retained resistance to 254-nm UV radiation, it did not, in contrast to the wild-type strain, show any excessive DNA degradation or cell death when incubated with chloramphenicol after sublethal doses of either UV light or mitomycin C. The results suggest the constitutive synthesis of an enzyme system responsible for wild-type proficiency in the repair of mitomycin C-induced damage. An alternative system able to repair damage caused by mitomycin C was demonstrated in the mtcA background. In this strain, additional damage inflicted upon the cellular DNA effected a massive rescue of cells previously inactivated by mitomycin C. Rescue was provoked by ionizing radiation, by UV light, or by simple alkylating agents. Cells treated with psoralen plus near-UV radiation could be rescued only when inactivation was due primarily to psoralen-DNA interstrand cross-links rather than to monoadducts. The rescue of inactivated cells was prevented in the presence of chloramphenicol. These results can be interpreted most readily in terms of an alternative repair system able to overcome DNA interstrand cross-links produced by mitomycin C or psoralen plus near-UV light, but induced only by the more abundant number of damages produced by radiation or simple alkylating agents.

Diverse applications of covalent cross-links in duplex DNA: From anti-cancer drugs to the detection of disease-relevant single nucleotide polymorphisms to the synthesis of well-defined substrates for the study of novel DNA repair processes

2018 ◽  
Author(s):  
◽  
Maryam Imani Nejad
Keyword(s):  
Excision Repair ◽  
Alkylating Agents ◽  
Nucleotide Polymorphisms ◽  
Cross Link ◽  
Single Nucleotide ◽  
Synthetic Dna ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
Ap Sites ◽  
Cellular Dna

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Abasic (Ap) sites are a common form of DNA lesion that occur endogenously 50,000-200,000 per cell per day in mammals. The alkylation of the guanine and adenine residues by the alkylating agents such as nitrogen mustards also induces the formation of Ap sites in genomic DNA. Our group recently showed that Ap sites can forge DNA-DNA interstrand cross-links in some sequences via reaction of the Ap aldehyde residue with the exocyclic amino groups of nucleobases, such as adenine and guanine, on the opposing strand of the DNA duplex. The earlier work in the group revealed that formation of these covalent bridges between two DNA strands is highly sequence- dependent. Although interstrand cross-links are one of the most deleterious types of cellular DNA damage, the availability of synthetic DNA duplexes containing chemically well-defined, site-specific interstrand cross-links has been proven to be a valuable tool in biological chemistry and medicine. We prepared and characterized a new Ap-derived interstrand cross-link. In another project, we use these remarkable cross-linking reactions for the covalent capture of disease-relevant single nucleotide polymorphism by using a protein nanopore technology. The complex mechanisms underlying cross-link repair in cells and limited availability of stable and defined cross-link are two major reasons why repair pathways of these lesions are not yet well understood. By preparing a variety of Ap-derived cross-links, we studied the role of a base excision repair DNA glycosylase, NEIL3 in unhooking the lesions.

Formation of DNA interstrand cross-links as a marker of Mitomycin C bioreductive activation and chemosensitivity

2005 ◽  
Vol 41 (9) ◽  
pp. 1331-1338 ◽  
Author(s):  
Milène Volpato ◽  
Jill Seargent ◽  
Paul M. Loadman ◽  
Roger M. Phillips
Keyword(s):  
Mitomycin C ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
Bioreductive Activation

scholarly journals Disruption of Mouse SNM1 Causes Increased Sensitivity to the DNA Interstrand Cross-Linking Agent Mitomycin C

2000 ◽  
Vol 20 (13) ◽  
pp. 4553-4561 ◽  
Author(s):  
Mies L. G. Dronkert ◽  
Jan de Wit ◽  
Miranda Boeve ◽  
M. Luisa Vasconcelos ◽  
Harry van Steeg ◽  
...  
Keyword(s):  
Mitomycin C ◽  
Nuclear Protein ◽  
Embryonic Stem ◽  
Antitumor Therapy ◽  
Fusion Construct ◽  
Nucleotide Excision ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
Increased Sensitivity ◽  
Genomic Cdna

ABSTRACT DNA interstrand cross-links (ICLs) represent lethal DNA damage, because they block transcription, replication, and segregation of DNA. Because of their genotoxicity, agents inducing ICLs are often used in antitumor therapy. The repair of ICLs is complex and involves proteins belonging to nucleotide excision, recombination, and translesion DNA repair pathways in Escherichia coli, Saccharomyces cerevisiae, and mammals. We cloned and analyzed mammalian homologs of the S. cerevisiae gene SNM1(PSO2), which is specifically involved in ICL repair. Human Snm1, a nuclear protein, was ubiquitously expressed at a very low level. We generated mouse SNM1−/− embryonic stem cells and showed that these cells were sensitive to mitomycin C. In contrast to S. cerevisiae snm1 mutants, they were not significantly sensitive to other ICL agents, probably due to redundancy in mammalian ICL repair and the existence of other SNM1homologs. The sensitivity to mitomycin C was complemented by transfection of the human SNM1 cDNA and by targeting of a genomic cDNA-murine SNM1 fusion construct to the disrupted locus. We also generated mice deficient for murine SNM1. They were viable and fertile and showed no major abnormalities. However, they were sensitive to mitomycin C. The ICL sensitivity of the mammalian SNM1 mutant suggests that SNM1function and, by implication, ICL repair are at least partially conserved between S. cerevisiae and mammals.

scholarly journals The Structure-Specific Endonuclease Ercc1-Xpf Is Required To Resolve DNA Interstrand Cross-Link-Induced Double-Strand Breaks

2004 ◽  
Vol 24 (13) ◽  
pp. 5776-5787 ◽  
Author(s):  
Laura J. Niedernhofer ◽  
Hanny Odijk ◽  
Magda Budzowska ◽  
Ellen van Drunen ◽  
Alex Maas ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Strand Break ◽  
Sister Chromatid Exchanges ◽  
Wild Type ◽  
Cross Link ◽  
Interstrand Cross Links ◽  
Normal Metabolism ◽  
Cross Links

ABSTRACT Interstrand cross-links (ICLs) are an extremely toxic class of DNA damage incurred during normal metabolism or cancer chemotherapy. ICLs covalently tether both strands of duplex DNA, preventing the strand unwinding that is essential for polymerase access. The mechanism of ICL repair in mammalian cells is poorly understood. However, genetic data implicate the Ercc1-Xpf endonuclease and proteins required for homologous recombination-mediated double-strand break (DSB) repair. To examine the role of Ercc1-Xpf in ICL repair, we monitored the phosphorylation of histone variant H2AX (γ-H2AX). The phosphoprotein accumulates at DSBs, forming foci that can be detected by immunostaining. Treatment of wild-type cells with mitomycin C (MMC) induced γ-H2AX foci and increased the amount of DSBs detected by pulsed-field gel electrophoresis. Surprisingly, γ-H2AX foci were also induced in Ercc1 −/− cells by MMC treatment. Thus, DSBs occur after cross-link damage via an Ercc1-independent mechanism. Instead, ICL-induced DSB formation required cell cycle progression into S phase, suggesting that DSBs are an intermediate of ICL repair that form during DNA replication. In Ercc1 −/− cells, MMC-induced γ-H2AX foci persisted at least 48 h longer than in wild-type cells, demonstrating that Ercc1 is required for the resolution of cross-link-induced DSBs. MMC triggered sister chromatid exchanges in wild-type cells but chromatid fusions in Ercc1 −/− and Xpf mutant cells, indicating that in their absence, repair of DSBs is prevented. Collectively, these data support a role for Ercc1-Xpf in processing ICL-induced DSBs so that these cytotoxic intermediates can be repaired by homologous recombination.

scholarly journals DNA Damage Induced by Alkylating Agents and Repair Pathways

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Natsuko Kondo ◽  
Akihisa Takahashi ◽  
Koji Ono ◽  
Takeo Ohnishi
Keyword(s):  
Dna Damage ◽  
Dna Methyltransferase ◽  
Clinical Medicine ◽  
Excision Repair ◽  
Alkylating Agents ◽  
Complementation Group ◽  
Clear Understanding ◽  
Repair System ◽  
Cellular Dna ◽  
Methylating Agents

The cytotoxic effects of alkylating agents are strongly attenuated by cellular DNA repair processes, necessitating a clear understanding of the repair mechanisms. Simple methylating agents form adducts atN- andO-atoms.N-methylations are removed by base excision repair, AlkB homologues, or nucleotide excision repair (NER).O6-methylguanine (MeG), which can eventually become cytotoxic and mutagenic, is repaired byO6-methylguanine-DNA methyltransferase, andO6MeG:T mispairs are recognized by the mismatch repair system (MMR). MMR cannot repair theO6MeG/T mispairs, which eventually lead to double-strand breaks. Bifunctional alkylating agents form interstrand cross-links (ICLs) which are more complex and highly cytotoxic. ICLs are repaired by complex of NER factors (e.g., endnuclease xeroderma pigmentosum complementation group F-excision repair cross-complementing rodent repair deficiency complementation group 1), Fanconi anemia repair, and homologous recombination. A detailed understanding of how cells cope with DNA damage caused by alkylating agents is therefore potentially useful in clinical medicine.

scholarly journals Initiation of DNA interstrand cross-link repair in humans: the nucleotide excision repair system makes dual incisions 5' to the cross-linked base and removes a 22- to 28-nucleotide-long damage-free strand.

1997 ◽  
Vol 17 (12) ◽  
pp. 6822-6830 ◽  
Author(s):  
T Bessho ◽  
D Mu ◽  
A Sancar
Keyword(s):  
Dna Repair ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Repair System ◽  
Cross Link ◽  
Unique Challenge ◽  
Cell Extracts ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
The Cross

Most DNA repair mechanisms rely on the redundant information inherent to the duplex to remove damaged nucleotides and replace them with normal ones, using the complementary strand as a template. Interstrand cross-links pose a unique challenge to the DNA repair machinery because both strands are damaged. To study the repair of interstrand cross-links by mammalian cells, we tested the activities of cell extracts of wild-type or excision repair-defective rodent cell lines and of purified human excision nuclease on a duplex with a site-specific cross-link. We found that in contrast to monoadducts, which are removed by dual incisions bracketing the lesion, the cross-link causes dual incisions, both 5' to the cross-link in one of the two strands. The net result is the generation of a 22- to 28-nucleotide-long gap immediately 5' to the cross-link. This gap may act as a recombinogenic signal to initiate cross-link removal.

scholarly journals DNA interstrand cross-links induced by the major oxidative adenine lesion 7,8-dihydro-8-oxoadenine

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aaron L. Rozelle ◽  
Young Cheun ◽  
Caroline K. Vilas ◽  
Myong-Chul Koag ◽  
Seongmin Lee
Keyword(s):  
Biological Effects ◽  
Alkylating Agents ◽  
Nucleophilic Attack ◽  
Interstrand Cross Links ◽  
Reactive Halogen Species ◽  
Oxidative Activation ◽  
Cross Links ◽  
Covalently Linked ◽  
Oxidative Damage To Dna ◽  
Halogen Species

AbstractOxidative damage to DNA generates 7,8-dihydro-8-oxoguanine (oxoG) and 7,8-dihydro-8-oxoadenine (oxoA) as two major lesions. Despite the comparable prevalence of these lesions, the biological effects of oxoA remain poorly characterized. Here we report the discovery of a class of DNA interstrand cross-links (ICLs) involving oxidized nucleobases. Under oxidative conditions, oxoA, but not oxoG, readily reacts with an opposite base to produce ICLs, highlighting a latent alkylating nature of oxoA. Reactive halogen species, one-electron oxidants, and the myeloperoxidase/H2O2/Cl− system induce oxoA ICLs, suggesting that oxoA-mediated cross-links may arise endogenously. Nucleobase analog studies suggest C2-oxoA is covalently linked to N2-guanine and N3-adenine for the oxoA-G and oxoA-A ICLs, respectively. The oxoA ICLs presumably form via the oxidative activation of oxoA followed by the nucleophilic attack by an opposite base. Our findings provide insights into oxoA-mediated mutagenesis and contribute towards investigations of oxidative stress-induced ICLs and oxoA-based latent alkylating agents.

scholarly journals Lack of correlation between repair of DNA interstrand cross-links and hypersensitivity of hamster cells towards mitomycin C and cisplatin

FEBS Letters ◽  
1998 ◽  
Vol 437 (1-2) ◽  
pp. 97-100 ◽  
Author(s):  
Florence Larminat ◽  
Gilles Cambois ◽  
Małgorzata Z. Zdzienicka ◽  
Martine Defais
Keyword(s):  
Mitomycin C ◽  
Interstrand Cross Links ◽  
Cross Links

scholarly journals Nucleotide Excision Repair- and Polymerase η-Mediated Error-Prone Removal of Mitomycin C Interstrand Cross-Links

2003 ◽  
Vol 23 (2) ◽  
pp. 754-761 ◽  
Author(s):  
Huyong Zheng ◽  
Xin Wang ◽  
Amy J. Warren ◽  
Randy J. Legerski ◽  
Rodney S. Nairn ◽  
...  
Keyword(s):  
Mitomycin C ◽  
Nucleotide Excision Repair ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Double Helix ◽  
Dna Lesions ◽  
Nucleotide Excision ◽  
Interstrand Cross Links ◽  
Cross Links

ABSTRACT Interstrand cross-links (ICLs) make up a unique class of DNA lesions in which both strands of the double helix are covalently joined, precluding strand opening during replication and transcription. The repair of DNA ICLs has become a focus of study since ICLs are recognized as the main cytotoxic lesion inflicted by an array of alkylating compounds used in cancer treatment. As is the case for double-strand breaks, a damage-free homologous copy is essential for the removal of ICLs in an error-free manner. However, recombination-independent mechanisms may exist to remove ICLs in an error-prone fashion. We have developed an in vivo reactivation assay that can be used to examine the removal of site-specific mitomycin C-mediated ICLs in mammalian cells. We found that the removal of the ICL from the reporter substrate could take place in the absence of undamaged homologous sequences in repair-proficient cells, suggesting a cross-link repair mechanism that is independent of homologous recombination. Systematic analysis of nucleotide excision repair mutants demonstrated the involvement of transcription-coupled nucleotide excision repair and a partial requirement for the lesion bypass DNA polymerase η encoded by the human POLH gene. From these observations, we propose the existence of a recombination-independent and mutagenic repair pathway for the removal of ICLs in mammalian cells.

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