Induction of sister chromatid exchanges and chromosome aberrations in cho cells arrested in the cell cycle by arginine deprivation |
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Authors: | W Donald Macrae E A Mackinnon H F Stich |
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Institution: | (1) Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada;(2) Anatomy Department, Queen's University, Kingston, Ontario, Canada |
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Abstract: | Summary Sister chromatid exchanges (SCE) and chromosome aberrations were induced in nondividing CHO cells that had been arrested in
their cell cycle by deprivation of the essential amino acid arginine. Cells arrested in arginine-deficient medium (ADM) were
treated with one of the mutagenic agents N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) or mitomycin C (MMC) and refed with complete
medium; the recovering cell population was sampled at various intervals thereafter and mitotic cells analyzed for the presence
of chromosome aberrations and SCE. Both chemicals were observed to cause delays in the cell cycle of recovering cells and
to induce, chromosome aberrations and SCE at low doses. We have described the variation in the incidence of chromosome aberrations
and SCE with respect to sampling time and the number of cell cycles traversed. When ADM-arrested CHO cells were treated with
three mutagens at various intervals either before or after release from ADM, it was observed that: (a) UV light induced the
greatest number of SCE when applied to cells undergoing DNA synthesis, and SCE yeilds induced by this agent could be reduced
by postirradiation incubation in ADM; (b) MNNG induced fewer SCE when applied to cells undergoing DNA synthesis, and SCE yields
induced by this agent could not be reduced by posttreatment incubation in ADM for 24 hr. (c) MMC induced the same level irrespective
of the time of exposure, and SCE yields induced by this agent could not be reduced by posttreatment incubation in ADM for
24 hr.
This work was supported by grants from the British Columbia Foundation for Non-Animal Research (to W. D. M.), and the National
Cancer Institute of Canada and the National Research Council of Canada (to H. F. S.). Professor H. F. Stich is a Research
Associate of the NCI. |
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Keywords: | SCE chromosome aberrations arginine deprivation G1 arrest |
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