| Project/Area Number |
07558200
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | Tohoku University |
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Principal Investigator |
ONO Tetsuya Tohoku Univ.Sch.Med., Professor, 医学部, 教授 (00107509)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Hiroaki Toyobo Inc., Major Investigator, 主任部員
YAMAMOTO Kazuo Grad.Sch.Sci., Tohoku Univ., Professor, 大学院・理学研究科, 教授 (20093536)
SOFUNI Toshio Div.Genetics & Mutagenesis, Nat.Inst.Health Science, Head, 安全性生物試験セ・変異遺伝部, 部長 (20132889)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1996: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Environmental Mutagen / Radiation / Deletion / LacZ / Spi Assay / Transgenic Mouse / 環境変異原物質 / 突然変異 / プラスミド / シャトルベクター |
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| Research Abstract |
Understanding risk factors of environmental mutagens on human being is one of the most urgent subjects. Among many questions which have to be elucidated, mutation induction in diffirent tissues of a body is the least understood point. In order to solve this problem, several transgenic mice have been created since 1989. But all of these mice are inefficient in detecting deletion-type mutation. To overcome this problem, J.Vijg's group has developed a plasmid based new transgenic mice (Ingeno). Theoretically, this mouse seemed to solve the problem. So we introduced them and asked if they can detect radiation-induced mutation efficiently. First we tried 4Gy of irradiation and fornd it is not sufficient to observe significant induction of mutation above spontaneous level. We raised the dose to 50Gy and 100Gy and could find a significant increase in spleen and brain. The increase of mutant frequency reached plateau levels 2.5 to 3.5 days after irradiation. The dose responses were almost linear with 50 and 100Gy of irradiation. The rates of induction per Gy were 0.2 times and 0.15 times of spontaneous level in spleen and brainrespectively, which were much lower than those found previously in native genes like GPT,H-2K etc. Examination of mutant DNAs by gel electrophoresis showed that most of the mutants were deletion type mutation rather than small mutation. From these data we have reached a conclusion that Ingeno mouse can detect deletion type but the sensitivity is not high enough to detect the amount of mutation induced by sublethal dose of ionizing radiation. To get over the problem, we have created a new transgenic mouse (Gpt-Delta) which utilizes Spi assay for mutation detection. This mouse showed low level of spontaneous mutant frequency and high sensitivity to radiation. The detailed studies are now on progress.
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