DNA-repair synthesis in ataxia telangiectasis lymphoblastoid cells

The ability of a number of Epstein-Barr virus-transformed lymphoblastoid cells from ataxia telangiectasis (AT) patients to repair gamma-radiation damage to DNA was determined. All of these AT cells were previously shown to be hypersensitive to gamma-radiation. Two methods were used to determine DNA-repair synthesis: isopycnic gradient analysis and a method employing hydroxyurea to inhibit semiconservative DNA synthesis. Control, AT heterozygote and AT homozygote cells were demonstrated to have similar capacities for repair of radiation damage to DNA. In addition at high radiation doses (10-40 krad) the extent of inhibition of DNA synthesis was similar in the different cell types.