INDUCTION OF DNA BREAKAGE IN X-IRRADIATED NUCLEOIDS SELECTIVELY STRIPPED OF NUCLEAR PROTEINS IN 2 MOUSE LYMPHOMA CELL-LINES DIFFERING IN RADIOSENSITIVITY
M. Kruszewski et T. Iwanenko, INDUCTION OF DNA BREAKAGE IN X-IRRADIATED NUCLEOIDS SELECTIVELY STRIPPED OF NUCLEAR PROTEINS IN 2 MOUSE LYMPHOMA CELL-LINES DIFFERING IN RADIOSENSITIVITY, Acta Biochimica Polonica, 45(3), 1998, pp. 701-704
The role of nuclear proteins in protection of DNA against ionizing rad
iation and their contribution to the radiation sensitivity was examine
d by an alkaline version of comet assay in two L5178Y (LY) mouse lymph
oma cell lines differing in sensitivity to ionizing radiation, LY-S ce
lls are twice more sensitive to ionizing radiation than LY-R cells (Do
values of survival curves are 0.5 Gy and 1 Gy, respectively). Sequent
ial removal of nuclear proteins by extraction with NaCl of different c
oncentrations increased the X-ray induced DNA damage in LY-R nucleoids
. In contrast, in the radiation sensitive LY-S cell line, depletion of
nuclear proteins practically did not affect DNA damage. Although ther
e is no doubt that the main cause of LY-S cells' sensitivity to ionizi
ng radiation is a defect in the repair of double-strand breaks, our da
ta support, the concept that nuclear matrix organisation may contribut
e to the cellular susceptibility to DNA damaging agents.