Evidence for two independent pathways of biologically effective excision repair from its rate and extent in cells cultured from sun-sensitive humans
Repair-proficient human cells can be sensitized to exposure to UV radiation at 254 nm by postirradiation incubation in the presence of the eukaryotic alpha polymerase inhibitor, aphidicolin. The degree of sensitization has been examined in cells cultured from humans suffering from various types of sun-sensitive syndromes. Xeroderma pigmentosum (XP) variant and Bloom's cell lines (both excision proficient) were strongly sensitized by aphidicolin. An excision repair proficient Cockayne's cell line and a deficient XPD line were both sensitized to a level similar to the sensitivity of excision deficient XPA cells. In contrast, three XPC cell lines which show intermediate UV-induced repair replication and UV sensitivity were sensitized little (in one case) or not at all (in two cases) to UV by postirradiation inhibition of the alpha polymerase. These results lead us to conclude that there are two independent pathways of biologically effective excision repair, the major one of which involves the alpha polymerase and a second, less efficient and slower pathway which is independent of the alpha polymerase and which is the only pathway operating in two of the three XPC strains tested. The rates of biologically effective excision repair were similar in normal, XP variant, and Cockayne's cell lines, but these rates were considerably higher than published rates of dimer excision measured under similar conditions.
- Research Organization:
- Swiss Institute for Cancer Research, Epalinges/Lausanne
- OSTI ID:
- 6274284
- Journal Information:
- Cancer Res.; (United States), Journal Name: Cancer Res.; (United States) Vol. 47:14; ISSN CNREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BIOLOGICAL PATHWAYS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL CULTURES
DISEASES
DNA REPAIR
ELECTROMAGNETIC RADIATION
ENZYME INHIBITORS
MAMMALS
MAN
PRIMATES
RADIATIONS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
SKIN DISEASES
ULTRAVIOLET RADIATION
VERTEBRATES
XERODERMA PIGMENTOSUM
XP CELLS