Ionizing Radiation-Induced 6-Thioguanine-Resistant Clones in Synchronous CHO Cells
- 1 January 1980
- journal article
- research article
- Published by JSTOR in Radiation Research
- Vol. 81 (1) , 76-84
- https://doi.org/10.2307/3575363
Abstract
When cultured Chinese hamster ovary (CHO) cells are exposed to acute doses of ionizing radiation at different times during the cell division cycle, there is a characteristic cell-cycle response for radiation-induced cell killing and induced resistance to 6-thioguanine (6TG). For cell killing the sensitive periods of the cell cycle are the G1, G2, M and early S periods. For mutation induction the sensitive stage is the G1 period with the maximum sensitivity near the boundary between the G1 and the S period. Cells appear to be very refractile to induction of 6TG resistance in other periods of the cell cycle. Chromosomal rearrangements of the X chromosome are most likely to occur in the G1 period before the gene for hypoxanthine guanine phosphoribosyltransferase (EC 2.4.2.8) replicates, most likely due to genetic recombination. Clones resistant to 6TG after exposure to X rays are most likely induced by a different mutagenic pathway than ones stimulated by UV or ethylnitrosourea treatments, since the mutation induction patterns in the cell cycle are quite different.This publication has 3 references indexed in Scilit:
- Evidence that spontaneous mitotic recombination occurs at the two-strand stage.Proceedings of the National Academy of Sciences, 1978
- Analyses of differential sensitivities of synchronized HeLa S3 cells to radiations and chemical carcinogens during the cell cycle Part IV. X-raysMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1977
- X-Ray and Ultraviolet Sensitivity of Synchronized Chinese Hamster Cells at Various Stages of the Cell CycleBiophysical Journal, 1965