| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1996: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
1) Comparison of spontaneous mutation rate in somatic cell of normal and XPA mice : To measure the mutation rate in mouse, we obtained XPA mice having rpsL gene as a reporter gene by crossing the XPA mice and rpsL transgenic mice. We prepared DNAs from brain, liver, kidney, testis, spleen and skin from 20 weeks-old mice of each genotype of XPA gene. Mutation rates of each tissues were as follow ; brain and liver : 3-4 x 10^<-4> ; kidney, testis, skin : 1-2 x 10^<-4> ; spleen : 3 x 10^<-5>. Differences of the mutation rates were not observed between normal and XPA mice.
2) UV-induced skin carcinogenesis and mutation : UV-irradiation (2000 J/m^2,3 times a week) led skin carcinogenesis only in the XPA mice after 20 weeks. All tumor induced by UV were squamous cell carcinomas. We analyzed the p53 gene of the tumors by PCR and direct sequencing. Nineteen out of 40 tumor contained mutation of the p53 gene. All mutations except one were occurred in pyrimidine run, indicating the mutations were induced by UV light. We treated XPA mice having rpsL transgene with UV at 2000 J/m^2 3 times a week. DNAs were prepared from UV-irradiated and UV-non-irradiated region of the skin and used for measured mutation rate. We observed no difference in mutation rate of these skins. These results are apparently inconsistent of the results from the UV carcinogenesis experiments.
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