1. Department of Radiation Genetics; Graduate School of Medicine; Kyoto University; Yoshida Konoe Sakyo-ku Kyoto 606-8501 Japan
2. Centre for Frontier Research; National Institute of Genetics, ROIS; Yata 1111 Mishima Shizuoka 411-8540 Japan
3. Department of Genome Repair Dynamics; Radiation Biology Center; Kyoto University; Yoshida Konoe Sakyo-ku Kyoto 606-8501 Japan
4. Department of Mathematical and Life Sciences; Graduate School of Science; Hiroshima University; Higashi-Hiroshima 739-8526 Japan
5. Department of Genetics; SOKENDAI; Yata 1111 Mishima Shizuoka 411-8540 Japan
6. JST, PREST; 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
7. Laboratory of Molecular Pharmacology; Center for Cancer Research; National Cancer Institute, National Institutes of Health; Bethesda MD 20892 USA