Induction and repair of DNA strand breaks and 1-beta-D-arabinofuranosylcytosine-detectable sites in 40-75 kVp X-irradiated compared to /sup 60/Co gamma-irradiated human cell lines
We have compared the initial yield and subsequent enzymatic repair of DNA strand breaks and 1-beta-D-arabinofuranosylcytosine (araC)-detectable sites in cultured human cell lines after irradiation with soft (40-75 kVp) X rays and hard (/sup 60/Co) gamma rays, two forms of low-LET radiation whose average ionization densities differ by 15-fold. Incubation of X- or gamma-irradiated cell cultures in the presence of araC resulted in the accumulation of DNA single-strand interruptions, as measured by conventional velocity sedimentation analysis in alkaline sucrose gradients. Since the drug is a selective inhibitor of DNA polymerase alpha, this observation implicates polymerase alpha in the repair of radiogenic damage. Specifically, DNA repair analysis in X-ray-treated cells suggested that polymerase alpha is a key participant in the repair of a distinct, albeit structurally undefined, class of radioproducts (presumably a combination of double-strand breaks and alkali-stable lesions, but takes little, if any, part in the restitution of single-strand breaks induced by ionizing radiation. Accordingly, the drug did not significantly inhibit the repair of DNA damage in cultures exposed to less than or equal to 100 Gy of gamma radiation. A remarkable difference was evident with respect to the absolute yields of these two major classes of DNA injury--that is, araC-detectable sites and single-strand breaks--depending on the type of radiation administered. For the same dose, the level of araC-detectable sites found in cells treated with gamma rays was as much as 3.4 times lower than that observed in X-ray-exposed cells.
- Research Organization:
- Cross Cancer Institute, Edmonton, Alberta (Canada)
- OSTI ID:
- 6937074
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 114:1; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Aphidicolin inhibits repair of DNA in UV-irradiated human fibroblasts
Aphidicolin: an inhibitor of DNA repair in human fibroblasts
Related Subjects
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL CULTURES
COBALT 60
COBALT ISOTOPES
COMPARATIVE EVALUATIONS
DNA
DNA REPAIR
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
IN VITRO
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MAN
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PRIMATES
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RADIOISOTOPES
RECOVERY
REPAIR
STRAND BREAKS
VERTEBRATES
X RADIATION
YEARS LIVING RADIOISOTOPES