Ataxia-telangiectasia cells are not uniformly deficient in poly(ADP-ribose) synthesis following X-irradiation |
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Authors: | L A Zwelling D Kerrigan M R Mattern |
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Institution: | Division of Environmental Toxicology and Environmental Health, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa 199-01 Japan |
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Abstract: | Inducibility of 6-thioguanine-resistant (6TGr) mutants and single-strand scission of DNA by cadmium chloride (CdCl2) was investigated in cultured Chinese hamster V79 cells. Frequency of 6TGr mutants increased concentration dependently by 24-h treatment with CdCl2 up to 3 X 10(-6) M but decreased beyond 3 X 10(-6) M. Mutagenic potency of cadmium in the absence of S9 was about half that of benzoa]pyrene in the presence of S9 at equitoxic concentrations. Treatment of the cultured cells with cadmium after benzoa]pyrene treatment was not synergistic but additive to the mutagenicity of benzoa]pyrene. Single-strand scission of DNA by alkaline elution techniques was observed in the cells treated with CdCl2 for 2 h in a concentration-dependent manner. The single-strand scission by cadmium was detected only in combination with proteinase K digestion of the cell lysates, indicating formation of DNA--protein cross-linking by the metal. These biological and biochemical findings indicate that cadmium is mutagenic in mammalian cells, and its mutagenic effect seems to be accompanied by single-strand scission of DNA. |
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Keywords: | To whom all correspondence should be addressed |
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