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Normal rejoining of DNA strand breaks in ataxia telangiectasia fibroblast lines after low x-ray exposure

Journal Article · · Radiat. Res.; (United States)
DOI:https://doi.org/10.2307/3575473· OSTI ID:6318365
The alkaline elution method was used to measure the enzymatic repair of x-ray-induced DNA strand breaks in skin fibroblasts derived from human subjects afflicted with ataxia telangiectasia (AT). Monolayer cultures of normal control and AT cell lines were exposed acutely to moderately lethal (250-rad) and highly lethal (1250-rad) doses of 250-kV x rays under aerobic conditions. Upon receiving 250 rad, the control fibroblasts from a clinically normal donor rejoined all detectable single-strand breaks (plus alkali-labile bonds) within 30 to 60 min of incubation. When challenged with 1250 rad the kinetics of strand rejoining by the normal control cells were biphasic. For both exposures, no significant difference in either the rate or the extent of strand rejoining was detected between the normal cell line (GM38) and three mutant cell lines (AT2BE, AT3BI, AT4BI) belonging to the three known genetic complementation groups in AT. It would thus appear that the enhanced radiosensitivity of cultured AT cells does not stem from faulty rejoining of radiogenic DNA strand breaks.
OSTI ID:
6318365
Journal Information:
Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 86:3; ISSN RAREA
Country of Publication:
United States
Language:
English