DNA double-strand breaks measured in individual cells subjected to gel electrophoresis
- British Columbia Cancer Research Centre, Vancouver (Canada)
Microscopic examination of individual mammalian cells embedded in agarose, subjected to electrophoresis, and stained with a fluorescent DNA-binding dye provides a novel way of measuring DNA damage and more importantly, of assessing heterogeneity in DNA damage within a mixed population of cells. With this method, DNA double-strand breaks can be detected in populations of cells exposed to X-ray doses as low as 5 Gy. The radiation dose-response relationship for initial formation of double-strand breaks was identical for cell lines irradiated in G1, regardless of their sensitivity to killing by ionizing radiation. However, for cells irradiated in S phase, DNA migration was significantly reduced. For Chinese hamster V79 cells, Chinese hamster ovary cells, WiDr human colon carcinoma cells, and L5178Y-R mouse lymphoblastoid cells, S-phase DNA appeared to be about 3 times less sensitive to X-ray damage than DNA from other phases of the cell cycle. However, for the very radiosensitive L5178Y-S cells, the migration of replicating DNA was reduced only slightly. For Chinese hamster V79 and Chinese hamster ovary cells, damage was repaired at a similar rate in all cells of the population, and 85% of the breaks were rejoined within 2 h after irradiation. The radiosensitive L5178Y-S cells repaired damage more slowly than V79 or Chinese hamster ovary cells; 2 h after exposure to 50 Gy, approximately 50% of the damage was still present.
- OSTI ID:
- 5263193
- Journal Information:
- Cancer Research; (United States), Journal Name: Cancer Research; (United States) Vol. 51:17; ISSN 0008-5472; ISSN CNREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
CHO cell repair of single-strand and double-strand DNA breaks induced by $gamma$- and $alpha$-radiations
Chromosomal damage observed in first postirradiation metaphases of repair-proficient and -deficient cell lines
Related Subjects
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
CARCINOMAS
CHO CELLS
DIGESTIVE SYSTEM
DISEASES
DNA REPAIR
DOSE-RESPONSE RELATIONSHIPS
DOSES
ELECTROMAGNETIC RADIATION
ELECTROPHORESIS
GASTROINTESTINAL TRACT
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
HAMSTERS
INTESTINES
IONIZING RADIATIONS
LARGE INTESTINE
MAMMALS
MAN
MICE
NEOPLASMS
ORGANS
PRIMATES
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RECOVERY
REPAIR
RODENTS
STRAND BREAKS
TUMOR CELLS
VERTEBRATES
X RADIATION