Ionising irradiation acts primarily via induction of DNA damage, among which doublestrand
breaks are the most important lesions. These lesions may lead to lethal chromosome
aberrations, which are the main reason for cell inactivation. Double-strand breaks
can be repaired by several different mechanisms. The regulation of these mechanisms
appears be fairly different for normal and tumour cells. Among different cell lines
capacity of doublestrand break repair varies by only few percents and is known to
be determined mostly by genetic factors. Knowledge about doublestrand break repair
mechanisms and their regulation is important for the optimal application of ionising
irradiation in medicine.
Keywords
DNA double-strand breaks - cell inactivation - chromosome aberration - apoptosis -
G1 arrest - DNA repair - non-homologous endjoining - homologous recombination