Function of chromatin structure and dynamics in DNA damage, repair and misrepair: γ-rays and protons in action

According to their physical characteristics, protons and ion beams promise a revolution in cancer radiotherapy. Curing protocols however reflect rather the empirical knowledge than experimental data on DNA repair. This especially holds for the spatio-temporal organization of repair processes in the context of higher-order chromatin structure—the problematics addressed in this work. The consequences for the mechanism of chromosomal translocations are compared for gamma rays and proton beams.

► The majority of DSBs are repaired individually close to the sites of their origin.
► Decondensation of damaged chromatin domains can potentiate clustering of lesions.
► DSB clustering might increase the risk of chromatin translocation.
► Distances of lesions and higher-order chromatin structure influence DSB clustering.
► The conclusions seem to hold both for DSB damage caused by γ-radiation and protons.