| Project/Area Number |
03808024
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Osaka University |
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Principal Investigator |
TODO Takeshi Osaka University Assistant Dept. of Medicine, Professor, 医学部, 助手 (90163948)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1992: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1991: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | UV damage / DNA repair / Photoreactivating enzyme / Drosophila / ゲルシフト法 / DNA結合蛋白 |
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| Research Abstract |
Cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts ((6-4) photoproducts) are the two major classes of cytotoxic mutagenic and carcinogenic DNA photoproducts produced by ultraviolet light irradiation of cells. The phenomenon of photoreactivation, the reduction of the lethal and mutagenic effects of ultraviolet radiation by simultaneous or subsequent irradiation with near ultraviolet or visible light, has been identified in several organisms and in some cases the enzymes that catalyze this process have been characterized in sufficient detail. CPDs are the only known substrate for the photoreactivating enzymes so far analyzed and enzymatic photoreactivation of (6-4) photoproducts has not yet been reported.
Using gel shift assay we have identified two protein factors (Factor 1 and Factor 2) which bind specifically to UV-irradiated DNA. After purification we have determined the enzymatic activity of each factor.Factor 2 is a Drosophila homologue of photolyase (which photoreactivate CPDs). Factor 1 is a photoreactivating enzyme of (6-4) photoproduct. This is the first report of such photoreactivating activity specific for (6-4) photoproduct in any organism.
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