| Project/Area Number |
05454222
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hygiene
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| Research Institution | KANSAI MEDICAL UNIVERSITY |
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Principal Investigator |
TOKUNAGA Rikio Kansai Medical University, Hygiene, Professor, 医学部, 教授 (40121959)
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| Co-Investigator(Kenkyū-buntansha) |
KOHNO Hirao Kansai Medical University, Hygiene, Associate Professor, 医学部, 講師 (30148522)
TAKETANI Shigeru Kansai Medical University, Hygiene, Associate Professor, 医学部, 助教授 (20121949)
ENDO Yoko Kansai Medical University, Public Health, Research Associate, 医学部, 助手 (50193438)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1994: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1993: ¥3,500,000 (Direct Cost: ¥3,500,000)
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| Keywords | Chemical carcinogen / DNA adduct / Yeast / Cytochrome P450 / Ribonucleotide reductase / リボヌクレオチドレダクターゼ / 芳香属アミノ化合物 |
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| Research Abstract |
The process of chemically induced carcinogenesis is generally divided into initiation and promotion. DNA adduct formation is target tissues is considered to be the first step of initiation ; therefor, detection of adducts would indicate the risks of cancer from exposure to compounds. ^<32>P-Postlabeling analysis, which can detect a very low level of adducts in DNA is a useful tool to detect this step in the initiation of cancer. Heterologous expression of human and rodent P450s in mammalian cells and yeast has been reported. Yeast contains intracellular organelles similar to mammalian cells and can be well used as a simple model of eukaryotic cells. We developed the method to measure P450-mediated metabolism of chemicals to DNA binding derivatives, using the yeast expression system, and examined the formation of DNA adducts derived from MBOCA in yeast expressing recombinant P450s (2B5 and 1A1) . These results show that recombinant rabbit P450 2B5 exhibits a potential activation of MBOCA and that rat P450 1A1 has some effect. The use of yeast expressing recombinant P450s and ^<32>P-Postlabeling facilitates a simple search for chemicals with carcinogenic potential.
Ribonucleotide reductase (RNR) catalyzes the rate limiting step in the production of deoxyribonucleotides. RNR3 expression is inducible by DNA-damaging agents. We have constructed a fusion plasmid of 5'promoter region of RNR3 and lac Z,and measured beta-galactosidase activity in order to detect in-duction of RNR3 mRNA.We examined the induction of RNR3/lac Z in yeast upon exposure to various antitumor agents. We also examined RNR3 induction accompanied by P450 mediated activation of procarcinogen in yeast co-expressing rat CYP1A1 and RNR3/lacZ.
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