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The Effect of γ Radiation on DNA Methylation
John F. Kalinich, George N. Catravas and Stephen L. Snyder
Vol. 117, No. 2 (Feb., 1989), pp. 185-197
Published by: Radiation Research Society
Stable URL: http://www.jstor.org/stable/3577319
Page Count: 13
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The effect of 60 Co γ radiation on DNA methylation was studied in four cultured cell lines. In all cases a dose-dependent decrease in 5-methylcytosine was observed at 24, 48, and 72 h postexposure to 0.5-10 Gy. Nuclear DNA methyltransferase activity decreased while cytoplasmic activity increased in irradiated (10 Gy) V79A03 cells as compared to controls. No DNA demethylase activity was detected in the nuclei of control or irradiated V79A03 cells. Additionally, γ radiation resulted in the differentiation of C-1300 N1E-115 cells, a mouse neuroblastoma line, in a dose- and time-dependent manner. These results are consistent with the hypothesis that (1) genes may be turned on following radiation via a mechanism involving hypomethylation of cytosine and (2) radiation-induced hypomethylation results from decreased intranuclear levels of DNA methyltransferase.
Radiation Research © 1989 Radiation Research Society