| Project/Area Number |
60304095
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
放射線5生物学
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| Research Institution | Radiation Biology Center, Kyoto University |
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Principal Investigator |
IKENAGA Mituo Radiation Biology Center, Kyoto University, 国立大学(その他), 教授 (70025378)
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| Co-Investigator(Kenkyū-buntansha) |
IJIRI Ken-ichi Faculty of Science, University of Tokyo, 理学部, 講師 (40111447)
NISHIMOTO Takeharu Faculty of Medicine, Kyushu University, 独立専攻, 教授 (10037426)
ISHIZAKI Kanji Radiation Biology Center, Kyoto University, 放射線生物研究センター, 助手 (70111987)
TODO Takeshi Faculty of Medicine, Osaka University, 医学部, 助手 (90163948)
OHNISHI Takeo Department of Biology, Nara Medical University, 進学部, 助教授 (60094554)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1986: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1985: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | DNA repair mechanisms / Gene cloning / <O^6> -Methylguanine Methyltransferase / Pyrimidine dimer / Excision repair / 除去修復 / 電気穿孔法 |
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| Research Abstract |
This research group was organized to discuss and exchange informations in the field of DNA repair and related topics. The main objective of the research project is to elucidate the species specificity of DNA repair mechanisms in various organisms. The following results were obtained by the individual investigators.
1. Among a variety of modified DNA bases produced by alkylating agents, <O^6> -methylguanine is believed to be a major lethal, mutagenic and carcinogenic damage by these agents. <O^6> -Methylguanine is known to be repaired by a repair enzyme, <O^6> -methylguanine methyltransferase. The methyltransferase gene (ada gene) of E. coli has been recently cloned by Nakabeppu et al. We have constructed a plasmid on which the E. coli ada gene was linked with an SV40 promotor sequence and a poly(A) site. After transferring this plasmid into Mer-human HeLa MR cells, which are lacking methyltransferase activity, effective expression of E. coli methyltransferase activity was observed. Isolated stable transformants clones showed higher resistance to N-methyl-N'-nitro-N-nitrosoguanidine in colony formation and sister-chromatid exchange than the parent HeLa MR cells.
2. Methyltransferase activities were compared among 26 cultured cell strains derived from 17 different species, from human to fish. In general, cells from human and rat showed the highest enzyme activity, whereas cell strains from frog, hamster and dog showed the lowest activity.
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