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Takahashi A, Mori E, Ohnishi T. Phospho-Nbs1 and Mre11 proteins which recognize DSBs co-localize with γH2AX in the nucleus after heat treatment. ACTA ACUST UNITED AC 2007. [DOI: 10.4993/acrt.15.50] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Luo Q, Yang J, Zeng QL, Zhu XM, Qian YL, Huang HF. 50-Hertz electromagnetic fields induce gammaH2AX foci formation in mouse preimplantation embryos in vitro. Biol Reprod 2006; 75:673-80. [PMID: 16855210 DOI: 10.1095/biolreprod.106.052241] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Effects of electromagnetic fields (EMFs) on DNA damage in mammals are still controversial. In the present study, the effects of EMFs on DNA damage in preimplantation mouse embryos in vitro were investigated by using gammaH2AX foci formation, a new sensitive indicator for detecting DNA double-strand breaks (DSBs). The data obtained demonstrated that EMFs decreased the cleavage rate of preimplantation mouse embryos. This decreasing effect of EMFs was related to the DNA-damaging effect indicated by the induction of gammaH2AX foci formation in preimplantation mouse embryos. The inducing effects of EMFs on gammaH2AX foci formation could be inhibited by the treatment of noise MFs or wortmannin, a phosphatidylinositol 3-kinase (PI3K) family inhibitor. Furthermore, the data obtained also showed that EMFs could activate the DNA damage-repair mechanism by recruiting repair factor Rad50 to the damaged DNA sites to repair the corresponding DNA damage. These findings suggest that EMFs could cause DNA damage in preimplantation embryos in vitro and that the adverse effects of EMFs on development might at least partly act through DNA damage. The DNA damage induced by EMFs could be at least partly repaired by the natural activation of DNA damage-repair mechanism or prevented by the simultaneous treatment of noise magnetic fields.
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Affiliation(s)
- Qiong Luo
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310006, China
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Zhou C, Li Z, Diao H, Yu Y, Zhu W, Dai Y, Chen FF, Yang J. DNA damage evaluated by gammaH2AX foci formation by a selective group of chemical/physical stressors. Mutat Res 2006; 604:8-18. [PMID: 16423555 PMCID: PMC2756993 DOI: 10.1016/j.mrgentox.2005.12.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2005] [Revised: 11/11/2005] [Accepted: 12/01/2005] [Indexed: 05/06/2023]
Abstract
It has been reported that the phosphorylated form of histone variant H2AX (gammaH2AX) plays an important role in the recruitment of DNA repair and checkpoint proteins to sites of DNA damage, particularly at double strand breaks (DSBs). Using gammaH2AX foci formation as an indicator for DNA damage, several chemicals/stress factors were chosen to assess their ability to induce gammaH2AX foci in a 24h time frame in a human amnion FL cell line. Two direct-acting genotoxins, methyl methanesulfonate (MMS) and N-ethyl-N-nitrosourea (ENU), can induce gammaH2AX foci formation in a time- and dose-dependent manner. Similarly, an indirect-acting genotoxin, benzo[a]pyrene (BP), also induced the formation of gammaH2AX foci in a time- and dose-dependent manner. Another indirect genotoxin, 2-acetyl-aminofluorene (AAF), did not induce gammaH2AX foci formation in FL cells; however, AAF can induce gammaH2AX foci formation in Chinese hamster CHL cells. Neutral comet assays also revealed the induction of DNA strand breaks by these agents. In contrast, epigenetic carcinogens azathioprine and cyclosporine A, as well as non-carcinogen dimethyl sulfoxide, did not induce gammaH2AX foci formation in FL cells. In addition, heat shock and hypertonic saline did not induce gammaH2AX foci. Cell survival analyses indicated that the induction of gammaH2AX is not correlated with the cytotoxic effects of these agents/factors. Taken together, these results suggest that gammaH2AX foci formation could be used for evaluating DNA damage; however, the different cell types used may play an important role in determining gammaH2AX foci formation induced by a specific agent.
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Affiliation(s)
- Chunxian Zhou
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Zhongxiang Li
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Huiling Diao
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Yanke Yu
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Wen Zhu
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Yayun Dai
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Fanqing F. Chen
- Life Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94210, USA
| | - Jun Yang
- Department of Public Health, Institute for Toxicology, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
- Corresponding author. Tel.: +86 571 8721 7199; fax: +86 571 8721 7199. E-mail address: (J. Yang)
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Abdel-Halim HI, Mullenders LHF, Boei JJWA. Pairing of heterochromatin in response to cellular stress. Exp Cell Res 2006; 312:1961-9. [PMID: 16626698 DOI: 10.1016/j.yexcr.2006.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 01/27/2006] [Accepted: 02/24/2006] [Indexed: 12/16/2022]
Abstract
We previously reported that exposure of human cells to DNA-damaging agents (X-rays and mitomycin C (MMC)) induces pairing of the homologous paracentromeric heterochromatin of chromosome 9 (9q12-13). Here, we show that UV irradiation and also heat shock treatment of human cells lead to similar effects. Since the various agents induce very different types and frequencies of damage to cellular constituents, the data suggest a general stress response as the underlying mechanism. Moreover, local UV irradiation experiments revealed that pairing of heterochromatin is an event that can be triggered without induction of DNA damage in the heterochromatic sequences. The repair deficient xeroderma pigmentosum cells (group F) previously shown to fail pairing after MMC displayed elevated pairing after heat shock treatment but not after UV exposure. Taken together, the present results indicate that pairing of heterochromatin following exposure to DNA-damaging agents is initiated by a general stress response and that the sensing of stress or the maintenance of the paired status of the heterochromatin might be dependent on DNA repair.
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Affiliation(s)
- H I Abdel-Halim
- Department of Toxicogenetics, Leiden University Medical Center, PO Box 9503, 2300 RA Leiden, The Netherlands
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Yu Y, Zhu W, Diao H, Zhou C, Chen FF, Yang J. A comparative study of using comet assay and gammaH2AX foci formation in the detection of N-methyl-N'-nitro-N-nitrosoguanidine-induced DNA damage. Toxicol In Vitro 2006; 20:959-65. [PMID: 16473493 PMCID: PMC2757007 DOI: 10.1016/j.tiv.2006.01.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2005] [Revised: 12/11/2005] [Accepted: 01/05/2006] [Indexed: 02/06/2023]
Abstract
Comet assay is a useful technique in the detection of DNA damages, particularly DNA strand breaks; and it has been utilized to show that a potent carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), can induce such damages. Recently, gammaH2AX foci formation has been suggested as another sensitive way to detect DNA double strand breaks (DSBs). However, there is no systematic comparison being conducted to evaluate the consistency of these two methods. Using MNNG as a model chemical, the sensitivity of neutral comet assay and gammaH2AX foci formation in detecting MNNG-induced damage was studied. It was found that at concentrations of 0.1 and 1 microg/ml, both methods can detect MNNG-induced damage in human amnion FL cells. However, at 0.1 microg/ml, comet assay revealed more percentage of cells with DNA damage than gammaH2AX fluorescence revealed. On the other hand, while gammaH2AX foci were readily formed at very early times by 10 microg/ml MNNG treatment, neutral comet assay did not detect any significant DNA damage at the same time points. In addition, 10 microg/ml MNNG induced a distinct whole nuclei staining pattern of gammaH2AX, a type of DNA damage which was not detected by neutral comet assay but could be detected by alkaline comet assay. Therefore, gammaH2AX may be used as a sensitive indicator for DNA damage.
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Affiliation(s)
- Yanke Yu
- Department of Public Health, Center for Environmental Genomics, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Wen Zhu
- Department of Public Health, Center for Environmental Genomics, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Huiling Diao
- Department of Public Health, Center for Environmental Genomics, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Chunxian Zhou
- Department of Public Health, Center for Environmental Genomics, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
| | - Fanqing F. Chen
- Molecular Biology Branch, Life Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jun Yang
- Department of Public Health, Center for Environmental Genomics, Zhejiang University School of Medicine, 353 Yan An Road, Hangzhou, Zhejiang 310031, China
- Corresponding author. Tel./fax: +865718721 7194. E-mail address: (J. Yang)
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TAKAHASHI AKIHISA, OHNISHI TAKEO. What is the Critical Hyperthermia Target in Cancer Cells? ACTA ACUST UNITED AC 2006. [DOI: 10.3191/thermalmedicine.22.229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Takahashi A, Ohnishi T. Does gammaH2AX foci formation depend on the presence of DNA double strand breaks? Cancer Lett 2005; 229:171-9. [PMID: 16129552 DOI: 10.1016/j.canlet.2005.07.016] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Accepted: 07/10/2005] [Indexed: 10/25/2022]
Abstract
H2AX is a histone variant that is systematically found and ubiquitously distributed throughout the genome. Since it has been reported that DNA double-strand breaks (DSBs) induce phosphorylation of H2AX at serine 139 (gammaH2AX), an immunocytochemical assay with antibodies recognizing gammaH2AX has become the gold standard for the detection of DSBs. This assay is quite sensitive and is a specific indicator for the existence of a DSB. Until now, it has been reported that various kinds of physical, chemical, and biological factors induce the formation of the gammaH2AX foci detected using this assay. Even when gammaH2AX foci were detected, it was not always possible to conclude that the detected DSBs were produced by environmental stresses in the absence of any known radiation. In this review, emphasis is on discussing whether gammaH2AX foci formation depends on the formation of DSBs.
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Affiliation(s)
- Akihisa Takahashi
- Department of Biology, Nara Medical University School of Medicine, Shijo-cho 840, Kashihara, Nara 634-8521, Japan
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