Molecular characterization of x-ray induced mutations at the HGPRT locus in plateau phase Chinese hamster ovary cells: Effect of dose, dose fractionation, and delayed plating
Plateau-phase CHO-K1 cells were irradiated to study the effects of dose, dose fractionation and delayed plating on the yield and type of mutations induced by 250 kVp X rays at the HPRT locus. DNA isolated from 89 mutant cell lines was examined by Southern blot analysis using a cDNA HPRT probe. Complete loss of the HPRT locus was the most frequently observed lesion, regardless of treatment protocol. Dose was the only parameter tested which appeared to significantly affect the fraction of full deletions induced by X rays. At 2 Gy, only 43% (9/21) showed a complete loss of HPRT sequences. The proportion of full deletion mutants observed in all other treatment groups (4 Gy, 2 + 2 Gy separated by 24 h and 4 Gy with 24 h delay in replating) combined was 66% (45/68). The specific fraction of full deletions was not altered by repair associated with recovery from sublethal or potentially lethal damage, suggesting that while DNA repair may mitigate the lethal effects of radiation damage, it acts with equal fidelity on all lesions. Evidence will also be discussed which suggests that the distribution of intragenic lesions is nonrandom. 16 refs., 1 fig., 2 tabs.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830; AM06-70RL02225
- OSTI ID:
- 6203887
- Report Number(s):
- PNL-SA-16186; CONF-8904203-1; ON: DE89011208
- Country of Publication:
- United States
- Language:
- English
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Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
CELL CULTURES
CLONING
DNA HYBRIDIZATION
DNA REPAIR
DNA-CLONING
DOSE-RESPONSE RELATIONSHIPS
ELECTROMAGNETIC RADIATION
EVALUATION
FEMALE GENITALS
GONADS
HAMSTERS
HYBRIDIZATION
IONIZING RADIATIONS
MAMMALS
MUTATIONS
ORGANS
OVARIES
RADIATIONS
RADIOINDUCTION
RECOVERY
REPAIR
RODENTS
STRUCTURE-ACTIVITY RELATIONSHIPS
VERTEBRATES
X RADIATION