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Updated: Jul 28, 2026

Application of Laser Micro-irradiation for Examination of Single and Double Strand Break Repair in Mammalian Cells
Published on: September 5, 2017
Double base lesions in DNA X-irradiated in the presence or absence of oxygen
H C Box1, H B Patrzyc, J B Dawidzik
1Department of Molecular and Cellular Biophysics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
Abstract:
Previously, double lesions in which two adjacent bases are modified were identified in DNA oligomers exposed in solution to ionizing radiation. However, the formation of such lesions in polymer DNA had not been demonstrated. Using reference oligomer containing a specific double lesion and employing liquid chromatography-mass spectrometry (LC-MS), it was possible to show directly that double lesions are formed in irradiated calf thymus DNA. The double lesion in which a pyrimidine base is degraded to a formamido remnant and an adjacent guanine base is oxidized to 8-oxoguanine was detected in DNA X-irradiated in oxygenated aqueous solution. The double lesion in which the methyl carbon atom of a thymine base is covalently linked to carbon at the 8-position of an adjacent guanine base was detected in DNA irradiated in a deoxygenated environment.
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