Ion beam-induced DNA damage and its biological effects

イオンビーム誘発DNA損傷とその生物効果

鹿園 直哉

Shikazono, Naoya

After living cells are exposed to ionizing radiation, a variety of chemical modifications of DNA are induced either directly by ionization of DNA or indirectly through interactions with water-derived radicals. The DNA lesions include single strand breaks (SSB), base lesions, sugar damage, and apurinic/apyrimidinic sites (AP sites). It has been postulated that a significant amount of clustered DNA damage could be generated by ionizing radiation especially with that of high LET. Clustered DNA damage is defined as two or more lesions within one to two helical turns of DNA induced by a single radiation track. We are currently investigating non-DSB type of clustered DNA damage, as it has received less attention and its significance remains largely unknown. Our studies on the yield of non-DSB clustered damage induced by ion-particle irradiation as well as the biological consequences of non-DSB clustered DNA damage will be presented.