Repair of non-dimer DNA damages in ICB 2A frog cells exposed to solar-ultraviolet radiation in the UVB (290-320 nm) range

Book · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5005437

Chao, C C.K.

The purpose of the research described in this dissertation was to investigate the repair and cellular consequences of non-dimer DNA damages induced by solar-UV irradiation of cultured I CR 2A (Rana pipiens) frog cells. Because this cell line is proficient in enzymatic photoreactivation, it was possible to induce a relatively pure population of non-dimer DNA photoproducts by exposure of cells to the Mylar-filtered solar-UV wavelengths produced by a fluorescent sunlamp followed by treatment with photoreactivating light. With a modification of bromodeoxyuridine photolysis assay, it was found that the solar-UV-induced non-dimer DNA damages were repaired by a short-patch repair mechanism in which less than 20 nucleotides were inserted into a repaired region. Similar results were also obtained for ..gamma..-irradiated cells. In contrast, excision repair of 254 nm-induced dimers was accomplished by a long-patch process in which an average of about 180 nucleotides were inserted into the repaired sites. A mutant cell line, DRP 36, hypersensitive to non-dimer DNA damages, was isolated from I CR 2A cells. It was found that the DRP 36 cells performed a significantly lower level of excision repair following the induction of non-dimer DNA damages. The results are consistent with the conclusion that the DRP 36 cells are deficient in the repair of at least one type of solar-UV-induced non-dimer DNA lesion. These experiments indicate that solar-UV-induced non-dimer DNA photoproducts behave more like the photoproducts of ..gamma..-rays than those of far-UV radiation, which are primarily pyrimidine dimers.

• OSTI ID: 5005437
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMPHIBIANS
ANIMAL CELLS
ANIMALS
AQUATIC ORGANISMS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA
DNA REPAIR
ELECTROMAGNETIC RADIATION
FAR ULTRAVIOLET RADIATION
FROGS
GAMMA RADIATION
IONIZING RADIATIONS
MUTANTS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PHOTOREACTIVATION
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
ULTRAVIOLET RADIATION
VERTEBRATES