Isolation and Characterization of DNA Repair Deficient Mammalian Cell Mutants
Stevenson, Peter L.
MetadataShow full item record
UV-1 is a mutant of the Chinese Hamster Ovary cell line CHO-K1, which is hypersensitive to killing by ultraviolet radiation and ethyl methane sulfonate (EMS). DNA hydribization studies have shown UV-I and the CHO parent, 77256, to be competent in excision repair. Alkaline sucrose gradient sedimentation analysis has shown UV-1 to be significantly deficient in post-replicative repair. Preliminary genetic studies have indicated a lower rate of induced mutation to6-thioguanine (6-TG) resistance for UV-1 compared to the parent. This subsequent mutagenesis was undertaken to examine the mutability of UV-1 to a greater extent. UV-1 was found indeed to be hypomutable with respect to 6-TG resistance and also to be hypomutable to ouabain resistance when compared to the parent. Thus, UV-1 appears to be hypomutable as a result of a deficiency in the post-replicative system of repair. In addition, a contingent experiment was performed to determine the optimum conditions for the isolation of mammalian cell repair deficient mutants by employing nitrocellulose filter DNA hybridization techniques. Further, using these optimum conditions, an attempt was made to isolate CHO repair deficient mutants.