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Otozai S, Ishikawa-Fujiwara T, Oda S, Kamei Y, Ryo H, Sato A, Nomura T, Mitani H, Tsujimura T, Inohara H, Todo T. p53-Dependent suppression of genome instability in germ cells. Mutat Res 2014; 760:24-32. [PMID: 24406868 DOI: 10.1016/j.mrfmmm.2013.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/02/2013] [Accepted: 12/27/2013] [Indexed: 06/03/2023]
Abstract
Radiation increases mutation frequencies at tandem repeat loci. Germline mutations in γ-ray-irradiated medaka fish (Oryzias latipes) were studied, focusing on the microsatellite loci. Mismatch-repair genes suppress microsatellite mutation by directly removing altered sequences at the nucleotide level, whereas the p53 gene suppresses genetic alterations by eliminating damaged cells. The contribution of these two defense mechanisms to radiation-induced microsatellite instability was addressed. The spontaneous mutation frequency was significantly higher in msh2(-/-) males than in wild-type fish, whereas there was no difference in the frequency of radiation-induced mutations between msh2(-/-) and wild-type fish. By contrast, irradiated p53(-/-) fish exhibited markedly increased mutation frequencies, whereas their spontaneous mutation frequency was the same as that of wild-type fish. In the spermatogonia of the testis, radiation induced a high level of apoptosis both in wild-type and msh2(-/-) fish, but negligible levels in p53(-/-) fish. The results demonstrate that the msh2 and p53 genes protect genome integrity against spontaneous and radiation-induced mutation by two different pathways: direct removal of mismatches and elimination of damaged cells.
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Affiliation(s)
- Shinji Otozai
- Department of Otorhinolaryngology and Head and Neck Surgery, Osaka University School of Medicine, Osaka 565-0871, Japan
| | - Tomoko Ishikawa-Fujiwara
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, B4, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shoji Oda
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
| | - Yasuhiro Kamei
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, B4, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Haruko Ryo
- Nomura Project, National Institute of Biomedical Innovation, Osaka 565-0085, Japan
| | - Ayuko Sato
- Department of Pathology, Hyogo College of Medicine, Hyogo 663-8501, Japan
| | - Taisei Nomura
- Nomura Project, National Institute of Biomedical Innovation, Osaka 565-0085, Japan
| | - Hiroshi Mitani
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
| | - Tohru Tsujimura
- Department of Pathology, Hyogo College of Medicine, Hyogo 663-8501, Japan
| | - Hidenori Inohara
- Department of Otorhinolaryngology and Head and Neck Surgery, Osaka University School of Medicine, Osaka 565-0871, Japan
| | - Takeshi Todo
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, B4, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Boisen AMZ, Shipley T, Jackson P, Wallin H, Nellemann C, Vogel U, Yauk CL, Hougaard KS. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells. Reprod Toxicol 2013; 41:45-8. [PMID: 23871697 DOI: 10.1016/j.reprotox.2013.06.068] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 06/04/2013] [Accepted: 06/07/2013] [Indexed: 11/29/2022]
Abstract
Inhalation of particles has been shown to induce mutations in the male germline in mice following both prenatal and adult exposures in several experiments. In contrast, the effects of particles on female germ cell mutagenesis are not well established. Germline mutations are induced during active cell division, which occurs during fetal development in females. We investigated the effects of prenatal exposure to carbon black nanoparticles (CB) on induction of mutations in the female mouse germline during fetal development, spanning the critical developmental stages of oogenesis. Pregnant C57BL/6J mice were exposed four times during gestation by intratracheal instillation of 67μg/animal of nanosized carbon black Printex90 or vehicle (gestation days 7, 10, 15 and 18). Female offspring were raised to maturity and mated with unexposed CBA males. Expanded simple tandem repeat (ESTR) germline mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring.
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