scholarly journals Cellular response to DNA damage is enhanced by the pR plasmid in mouse cells and in Escherichia coli.

1986 ◽  
Vol 6 (2) ◽  
pp. 586-592 ◽  
Author(s):  
L Marcucci ◽  
F Gigliani ◽  
P A Battaglia ◽  
R Bosi ◽  
E Sporeno ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Statistical Analysis ◽  
Cellular Response ◽  
Regulatory Mechanism ◽  
Uv Light ◽  
Transformed Cells ◽  
Insertion Mutagenesis ◽  
Mouse Cells ◽  
Inducible Repair

The pR plasmid, which enhances the survival of Escherichia coli C600 exposed to UV light by induction of the SOS regulatory mechanism, showed the same effect when it transformed mouse LTA cells (tk-, aprt-). With Tn5 insertion mutagenesis which inactivates UV functions in the pR plasmid, we recognized two different regions of the plasmid, uvp1 and uvp2. These pR UVR- mutants exhibited the same effect in LTA transformed cells, demonstrating that resistance to UV light, carried by the pR plasmid, was really due to the expression of these two regions, which were also in the mouse cells. Statistical analysis showed that the expression of the uvp1 and uvp2 regions significantly increased (P less than 0.01) the survival upon exposure to UV light in mouse cells and bacteria. These results might suggest the presence of an inducible repair response to DNA damage in mouse LTA cells.

Cellular response to DNA damage is enhanced by the pR plasmid in mouse cells and in Escherichia coli

1986 ◽  
Vol 6 (2) ◽  
pp. 586-592
Author(s):  
L Marcucci ◽  
F Gigliani ◽  
P A Battaglia ◽  
R Bosi ◽  
E Sporeno ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Statistical Analysis ◽  
Cellular Response ◽  
Regulatory Mechanism ◽  
Uv Light ◽  
Transformed Cells ◽  
Insertion Mutagenesis ◽  
Mouse Cells ◽  
Inducible Repair

The pR plasmid, which enhances the survival of Escherichia coli C600 exposed to UV light by induction of the SOS regulatory mechanism, showed the same effect when it transformed mouse LTA cells (tk-, aprt-). With Tn5 insertion mutagenesis which inactivates UV functions in the pR plasmid, we recognized two different regions of the plasmid, uvp1 and uvp2. These pR UVR- mutants exhibited the same effect in LTA transformed cells, demonstrating that resistance to UV light, carried by the pR plasmid, was really due to the expression of these two regions, which were also in the mouse cells. Statistical analysis showed that the expression of the uvp1 and uvp2 regions significantly increased (P less than 0.01) the survival upon exposure to UV light in mouse cells and bacteria. These results might suggest the presence of an inducible repair response to DNA damage in mouse LTA cells.

Mutagenesis and More: umuDC and the Escherichia coli SOS Response

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1599-1610 ◽  
Author(s):  
Bradley T Smith ◽  
Graham C Walker
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Cellular Response ◽  
Sos Response ◽  
Posttranslational Regulation ◽  
E Coli ◽  
Sos Mutagenesis ◽  
Induced Mutagenesis ◽  
Mechanistic Basis ◽  
Increase Cell Survival

Abstract The cellular response to DNA damage that has been most extensively studied is the SOS response of Escherichia coli. Analyses of the SOS response have led to new insights into the transcriptional and posttranslational regulation of processes that increase cell survival after DNA damage as well as insights into DNA-damage-induced mutagenesis, i.e., SOS mutagenesis. SOS mutagenesis requires the recA and umuDC gene products and has as its mechanistic basis the alteration of DNA polymerase III such that it becomes capable of replicating DNA containing miscoding and noncoding lesions. Ongoing investigations of the mechanisms underlying SOS mutagenesis, as well as recent observations suggesting that the umuDC operon may have a role in the regulation of the E. coli cell cycle after DNA damage has occurred, are discussed.

scholarly journals A highly conserved endonuclease activity present in Escherichia coli, bovine, and human cells recognizes oxidative DNA damage at sites of pyrimidines.

1987 ◽  
Vol 7 (1) ◽  
pp. 26-32 ◽  
Author(s):  
P W Doetsch ◽  
W D Henner ◽  
R P Cunningham ◽  
J H Toney ◽  
D E Helland
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Uv Light ◽  
Human Fibroblasts ◽  
Human Cells ◽  
Sequence Specificity ◽  
Endonuclease Activity ◽  
E Coli ◽  
Endonuclease Iii

We have compared the sites of nucleotide incision on DNA damaged by oxidizing agents when cleavage is mediated by either Escherichia coli endonuclease III or an endonuclease present in bovine and human cells. E. coli endonuclease III, the bovine endonuclease isolated from calf thymus, and the human endonuclease partially purified from HeLa and CEM-C1 lymphoblastoid cells incised DNA damaged with osmium tetroxide, ionizing radiation, or high doses of UV light at sites of pyrimidines. For each damaging agent studied, regardless of whether the E. coli, bovine, or human endonuclease was used, the same sequence specificity of cleavage was observed. We detected this endonuclease activity in a variety of human fibroblasts derived from normal individuals as well as individuals with the DNA repair deficiency diseases ataxia telangiectasia and xeroderma pigmentosum. The highly conserved nature of such a DNA damage-specific endonuclease suggests that a common pathway exists in bacteria, humans, and other mammals for the reversal of certain types of oxidative DNA damage.

scholarly journals Topoisomerase III Acts Upstream of Rad53p in the S-Phase DNA Damage Checkpoint

2001 ◽  
Vol 21 (21) ◽  
pp. 7150-7162 ◽  
Author(s):  
Ronjon K. Chakraverty ◽  
Jonathan M. Kearsey ◽  
Thomas J. Oakley ◽  
Muriel Grenon ◽  
Maria-Angeles de la Torre Ruiz ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cellular Response ◽  
Cell Cycle Progression ◽  
Uv Light ◽  
S Phase ◽  
Dna Damaging Agents ◽  
Topoisomerase Iii ◽  
Rad53 Kinase ◽  
S Phase Checkpoint

ABSTRACT Deletion of the Saccharomyces cerevisiae TOP3gene, encoding Top3p, leads to a slow-growth phenotype characterized by an accumulation of cells with a late S/G2content of DNA (S. Gangloff, J. P. McDonald, C. Bendixen, L. Arthur, and R. Rothstein, Mol. Cell. Biol. 14:8391–8398, 1994). We have investigated the function of TOP3 during cell cycle progression and the molecular basis for the cell cycle delay seen in top3Δ strains. We show that top3Δ mutants exhibit a RAD24-dependent delay in the G2 phase, suggesting a possible role for Top3p in the resolution of abnormal DNA structures or DNA damage arising during S phase. Consistent with this notion,top3Δ strains are sensitive to killing by a variety of DNA-damaging agents, including UV light and the alkylating agent methyl methanesulfonate, and are partially defective in the intra-S-phase checkpoint that slows the rate of S-phase progression following exposure to DNA-damaging agents. This S-phase checkpoint defect is associated with a defect in phosphorylation of Rad53p, indicating that, in the absence of Top3p, the efficiency of sensing the existence of DNA damage or signaling to the Rad53 kinase is impaired. Consistent with a role for Top3p specifically during S phase, top3Δ mutants are sensitive to the replication inhibitor hydroxyurea, expression of the TOP3 mRNA is activated in late G1 phase, and DNA damage checkpoints operating outside of S phase are unaffected by deletion of TOP3. All of these phenotypic consequences of loss of Top3p function are at least partially suppressed by deletion of SGS1, the yeast homologue of the human Bloom's and Werner's syndrome genes. These data implicate Top3p and, by inference, Sgs1p in an S-phase-specific role in the cellular response to DNA damage. A model proposing a role for these proteins in S phase is presented.

scholarly journals Transgenic Expression of RecA of the Spirochetes Borrelia burgdorferi and Borrelia hermsii in Escherichia coli Revealed Differences in DNA Repair and Recombination Phenotypes

2004 ◽  
Vol 186 (8) ◽  
pp. 2266-2274 ◽  
Author(s):  
Adrienne D. Putteet-Driver ◽  
Jianmin Zhong ◽  
Alan G. Barbour
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Homologous Recombination ◽  
Borrelia Burgdorferi ◽  
Uv Light ◽  
Plasmid Vector ◽  
Borrelia Hermsii ◽  
Transgenic Expression ◽  
E Coli ◽  
Transgenic Cells

ABSTRACT After unsuccessful attempts to recover a viable RecA-deficient mutant of the Lyme borreliosis agent Borrelia burgdorferi, we characterized the functional activities of RecA of B. burgdorferi, as well as RecA of the relapsing fever spirochete Borrelia hermsii and the free-living spirochete Leptospira biflexa, in a recA mutant of Escherichia coli. As a control, E. coli RecA was expressed from the same plasmid vector. DNA damage repair activity was assessed after exposure of the transgenic cells to UV light or the radiomimetic chemicals methyl methanesulfonate and mitomycin C. Recombination activity in the cells was assessed by using an assay for homologous recombination between repeats in the chromosome and by measuring the ability of the cells to foster lytic growth by red gam mutant bacteriophage λ. Overall, we found that transgenic cells with recA genes of B. burgdorferi, B. hermsii, and L. biflexa had approximately equivalent activities in promoting homologous recombination in the lacZ duplication assay, but cells with B. burgdorferi recA and, most notably, B. hermsii recA were significantly less capable than cells with L. biflexa recA or E. coli recA in responding to DNA damage or in facilitating plaque formation in the phage assay. The comparatively poor function of Borrelia recA in the latter set of assays may be the consequence of impaired coordination in the loading of the transgenic RecA by RecBCD and/or RecFOR in E. coli.

scholarly journals Deletion of Mouse Rad9 Causes Abnormal Cellular Responses to DNA Damage, Genomic Instability, and Embryonic Lethality

2004 ◽  
Vol 24 (16) ◽  
pp. 7235-7248 ◽  
Author(s):  
Kevin M. Hopkins ◽  
Wojtek Auerbach ◽  
Xiang Yuan Wang ◽  
M. Prakash Hande ◽  
Haiying Hang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cellular Response ◽  
Gamma Ray ◽  
Uv Light ◽  
Ectopic Expression ◽  
Embryonic Stem ◽  
Cell Cycle Checkpoints ◽  
Genomic Integrity ◽  
Targeted Deletion ◽  
Spontaneous Chromosome

ABSTRACT The fission yeast Schizosaccharomyces pombe rad9 gene promotes cell survival through activation of cell cycle checkpoints induced by DNA damage. Mouse embryonic stem cells with a targeted deletion of Mrad9, the mouse ortholog of this gene, were created to evaluate its function in mammals. Mrad9 −/− cells demonstrated a marked increase in spontaneous chromosome aberrations and HPRT mutations, indicating a role in the maintenance of genomic integrity. These cells were also extremely sensitive to UV light, gamma rays, and hydroxyurea, and heterozygotes were somewhat sensitive to the last two agents relative to Mrad9 +/+ controls. Mrad9 −/− cells could initiate but not maintain gamma-ray-induced G2 delay and retained the ability to delay DNA synthesis rapidly after UV irradiation, suggesting that checkpoint abnormalities contribute little to the radiosensitivity observed. Ectopic expression of Mrad9 or human HRAD9 complemented Mrad9 −/− cell defects, indicating that the gene has radioresponse and genomic maintenance functions that are evolutionarily conserved. Mrad9 +/− mice were generated, but heterozygous intercrosses failed to yield Mrad9 −/− pups, since embryos died at midgestation. Furthermore, Mrad9 −/− mouse embryo fibroblasts were not viable. These investigations establish Mrad9 as a key mammalian genetic element of pathways that regulate the cellular response to DNA damage, maintenance of genomic integrity, and proper embryonic development.

scholarly journals Focus on UV-Induced DNA Damage and Repair—Disease Relevance and Protective Strategies

2020 ◽  
Vol 21 (19) ◽  
pp. 7264
Author(s):  
Mateusz Kciuk ◽  
Beata Marciniak ◽  
Mariusz Mojzych ◽  
Renata Kontek
Keyword(s):  
Dna Damage ◽  
Uv Radiation ◽  
Cellular Response ◽  
Current Knowledge ◽  
Uv Light ◽  
Environmental Pollutants ◽  
Ozone Layer ◽  
Special Focus ◽  
Dna Damage And Repair ◽  
Protective Strategies

The protective ozone layer is continually depleting due to the release of deteriorating environmental pollutants. The diminished ozone layer contributes to excessive exposure of cells to ultraviolet (UV) radiation. This leads to various cellular responses utilized to restore the homeostasis of exposed cells. DNA is the primary chromophore of the cells that absorbs sunlight energy. Exposure of genomic DNA to UV light leads to the formation of multitude of types of damage (depending on wavelength and exposure time) that are removed by effectively working repair pathways. The aim of this review is to summarize current knowledge considering cellular response to UV radiation with special focus on DNA damage and repair and to give a comprehensive insight for new researchers in this field. We also highlight most important future prospects considering application of the progressing knowledge of UV response for the clinical control of diverse pathologies.

scholarly journals Critical Role of DNA Checkpoints in Mediating Genotoxic-Stress–induced Filamentous Growth inCandida albicans

2007 ◽  
Vol 18 (3) ◽  
pp. 815-826 ◽  
Author(s):  
Qing-Mei Shi ◽  
Yan-Ming Wang ◽  
Xin-De Zheng ◽  
Raymond Teck Ho Lee ◽  
Yue Wang
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Dna Synthesis ◽  
Cellular Response ◽  
Uv Light ◽  
Critical Role ◽  
Genotoxic Stress ◽  
Filamentous Growth ◽  
Dna Damage Checkpoint ◽  
Fha Domain

The polymorphic fungus Candida albicans switches from yeast to filamentous growth in response to a range of genotoxic insults, including inhibition of DNA synthesis by hydroxyurea (HU) or aphidicolin (AC), depletion of the ribonucleotide-reductase subunit Rnr2p, and DNA damage induced by methylmethane sulfonate (MMS) or UV light (UV). Deleting RAD53, which encodes a downstream effector kinase for both the DNA-replication and DNA-damage checkpoint pathways, completely abolished the filamentous growth caused by all the genotoxins tested. Deleting RAD9, which encodes a signal transducer of the DNA-damage checkpoint, specifically blocked the filamentous growth induced by MMS or UV but not that induced by HU or AC. Deleting MRC1, the counterpart of RAD9 in the DNA-replication checkpoint, impaired DNA synthesis and caused cell elongation even in the absence of external genotoxic insults. Together, the results indicate that the DNA-replication/damage checkpoints are critically required for the induction of filamentous growth by genotoxic stress. In addition, either of two mutations in the FHA1 domain of Rad53p, G65A, and N104A, nearly completely blocked the filamentous-growth response but had no significant deleterious effect on cell-cycle arrest. These results suggest that the FHA domain, known for its ability to bind phosphopeptides, has an important role in mediating genotoxic-stress–induced filamentous growth and that such growth is a specific, Rad53p-regulated cellular response in C. albicans.

scholarly journals TEL/JAK2 tyrosine kinase inhibits DNA repair in the presence of amifostine.

2002 ◽  
Vol 49 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Ewa Gloc ◽  
Mariusz Warszawski ◽  
Wojciech Młynarski ◽  
Małgorzata Stolarska ◽  
Grazyna Hoser ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Tyrosine Kinase ◽  
Cellular Response ◽  
Catalytic Domain ◽  
Lymphoblastic Leukemia ◽  
Chromosomal Translocation ◽  
Cell Types ◽  
Transformed Cells ◽  
Dna Damage And Repair

The TEL/JAK2 chromosomal translocation (t(9;12)(p24;p13)) is associated with T cell childhood acute lymphoblastic leukemia. The TEL/JAK2 fusion protein contains the JAK2 catalytic domain and the TEL-specific oligomerization domain. TEL-mediated oligomerization of the TEL/JAK2 proteins results in the constitutive activation of the tyrosine kinase activity. Leukemia cells expressing TEL/JAK2 tyrosine kinase become resistant to anti-neoplastic drugs. Amifostine is a pro-drug which can selectively protect normal tissues against the toxicity of anticancer drugs and radiation. We investigated the effects of amifostine on idarubicin-induced DNA damage and repair in murine pro-B lymphoid BaF3 cells and BaF3-TEL/JAK2-transformed cells using alkaline single cell gel electrophoresis (comet assay). Idarubicin induced DNA damage in both cell types but amifostine reduced its extent in control non-transformed BaF3 cells and enhanced it in TEL/JAK2-transformed cells. The transformed cells did not show measurable DNA repair after exposure to amifostine and idarubicin, but cells treated only with idarubicin were able to recover within a 60-min incubation. Because TEL/JAK2-transformed cells can be considered as model cells for certain human leukemias and lymphomas we anticipate an enhancement of idarubicin cytotoxicity by amifostine in these diseases. Moreover, TEL/JAK2 tyrosine kinase might be involved in cellular response to DNA damage. Amifostine could promote apoptosis or lower the threshold for apoptosis induction dependent on TEL/JAK2 activation.

Inducible repair of oxidative DNA damage in Escherichia coli

Nature ◽  
1983 ◽  
Vol 304 (5925) ◽  
pp. 466-468 ◽  
Author(s):  
Bruce Demple ◽  
James Halbrook
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Inducible Repair
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