Host: The Japan Radiation Research Society, Chairman of the 52nd Annual Meeting, Toshiteru Okubo (Radiation Effects Research Foundation)
It is well known that high LET heavy particle radiation produces complex DNA lesions which are difficult to repair. Although many researches focused on complex DNA double strand breaks, our study presents complex DNA single strand breaks and base damages and homologous recombination repair. When cells were irradiated after G1-synchronization, heavy ions more efficiently inactivate cells and produce chromatid aberrations than x-ray does. In homologous recombination deficient cells, we observed significantly higher chromatid type aberrations after high LET exposure. This results suggested that DNA lesions formed in G1-phase were converted into DNA double strand breaks during DNA replication and they are complex single strand breaks or base damages produced by high LET radiation.
