EMS and UV-light-induced colony sectoring and delayed mutation in Chinese hamster cells
- 1 January 1998
- journal article
- review article
- Published by Taylor & Francis in International Journal of Radiation Biology
- Vol. 74 (6) , 739-745
- https://doi.org/10.1080/095530098141014
Abstract
Purpose: To review studies of mutagen-induced colony sectoring which demonstrate that UV light and EMS produce delayed mutational events in Chinese hamster ovary cells. Methods and results: Since the late 1940s, it has been known that the treatment of a single bacterial or yeast cell with mutagenic agents produces complete mutant colonies (pures) and colonies composed of both mutant and non-mutant cell types (mosaics) with various sectored patterns. A similar sectoring phenomenon has been observed in Chinese hamster ovary cells (CHO) using the DNA alkylating agent ethyl methane sulphonate (EMS) or ultraviolet light. However, unlike bacteria and yeast, a significant fraction of CHO mutant colonies contained sectors of less than 1/2; i.e. 1/4, 1/8 and 1/16 sectors, suggesting a delayed production of mutations. Using various colony-replating approaches, it was found that these mutagenic agents produced the ratio of mutant to wild-type cells expected for a delayed mutational process which produces mutant events for at least 12-14 cell divisions following treatment. This delayed mutation phenomenon was observed at both the glucose-6-phosphate dehydrogenase (G6PD) and hypoxanthine guanine phosphoribosyltransferase (HGPRT) loci. Various mutational mechanisms for the production of delayed mutations are discussed. Conclusions: These studies suggest that mutagens such as UV light and EMS induce long-term alterations in mammalian cells that act to increase the 'apparent' spontaneous mutation frequency. This delayed mutational decrease in stability of the genome may explain the accumulation over time of the multiple genetic changes observed in malignant tumours.Keywords
This publication has 27 references indexed in Scilit:
- Changing Views of Cellular RadiosensitivityRadiation Research, 1994
- Translesion DNA synthesis in the dihydrofolate reductase domain of UV-irradiated CHO cellsBiochemistry, 1992
- In vivo human somatic mutation: frequency and spectrum with ageMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1992
- Ascertainment of the effect of differential growth rates of mutants on observed mutant frequencies in X-irradiated mammalian cells An indication for the occurrence of X-ray-induced untargeted mutagenesisMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1983
- Sensitive determination of pyrimidine dimers in DNA of UV-irradiated mammalian cells Introduction of T4 endonuclease V into frozen and thawed cellsMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1981
- The repair hypothesis and the effect of caffeine on the induction of complete mutants in yeastMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1976
- A replica plating method for CHO cells using nylon clothCytogenetic and Genome Research, 1975
- UV-induced chromatid aberrations in cultured Chinese hamster cells after one, two, or three rounds of DNA replicationMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1974
- The production, by nitrous acid, of complete and mosaic mutations during defined nuclear stages in cells of Schizosaccharomyces pombeMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1970
- BACTERIAL VARIATIONAnnual Review of Microbiology, 1949