| Budget Amount *help |
¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2016: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2015: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2014: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2013: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2012: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
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| Outline of Final Research Achievements |
Radiation-induced biological effects are mainly caused by an accumulation of unrepaired DNA double-strand breaks (DSBs). DNA Ligase IV (Lig4) is one of the key protein of non-homologous end-joining (NHEJ), which is a major DSB repair pathway in mammalian cells. In this study, we found that the Lig4 mutated mice irradiated with low dose-rate γ-rays at 1 mGy/h died earlier than those irradiated with 1 Gy of X-rays at high dose-rate (0.5 Gy/min). We clarified that early exhaustion of hematopoietic stem cells due to accumulation of DNA damage and then acceleration of stem cell turnover was occurred in the Lig4 mutated mice under low dose-rate irradiation conditions as a cause of this. Our obtained results suggest that NHEJ is a chief DSB repair mechanism in maintaining the integrity of the genome under low dose-rate irradiation conditions.
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