title: Chinese hamster ovary mutant UV-1 is hypomutable and defective in a postreplication recovery process.
abstract: CHO-UV-1 is a mutant of the Chinese hamster cell CHO-K1 hypersensitive to killing by ultraviolet light but with normal resistance to X-ray. It is also hypersensitive to killing by ethyl methane sulfonate. Hybrid clones formed bu fusing UV-1 and Chinese hamster lung cells display the normal ultraviolet resistance of the latter. The sensitive phenotype behaves, therefore, in a genetically recessive manner. Ultraviolet sensitivity of UV-1 is not associated with a deficiency in excision repair. Alkaline sucrose gradient sedimentation analysis of nascent DNA from ultraviolet-irradiated cells reveals that UV-1 is, however, markedly deficient in postreplication recovery. Furthermore, UV-1 has a lower rate of induced mutation to 6-thioguanine resistance than does the parental cell when treated with ultraviolet light or ethyl methane sulfonate. These results suggest that the phenotype of UV-1 is due to a mutation in a form of postreplication recovery which in normal cells is error prone.
mesh_terms: D000818:Animals; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000032:analysis; D004260:DNA Repair; D005260:Female; D009154:Mutation; D010053:Ovary; D010641:Phenotype; D011836:Radiation Tolerance; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D004247:DNA