Ionizing radiation causes greater DNA base damage in radiation-sensitive mutant M10 cells than in parent mouse lymphoma L5178Y cells.

DNA base damage in radiation-sensitive mutant M10 cells and parent mouse lymphoma L5178Y cells was studied. Cells were exposed to ionizing radiation in the dose range of 48 to 400 Gy. Chromatin was isolated from cells and analyzed by gas chromatography-mass spectrometry. Ten DNA base products were identified and quantified. A dose-dependent formation of the products was observed. The yields of products in M10 cells were up to threefold greater than in L5178Y cells. Of the products measured, formamidopyrimidines had the highest difference in their yields between the two cell lines. The greater initial DNA base damage in M10 cells may play a role in their hypersensitivity to ionizing radiation.