Reaction of Nitrosoguanidine (N-Methyl-N'-Nitro-N-Nitrosoguanidine) with Tobacco Mosaic Virus and Its RNA

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Science  14 Jun 1968:
Vol. 160, Issue 3833, pp. 1235-1237
DOI: 10.1126/science.160.3833.1235


"Nitrosoguanidine" (N-methyl-N'-nitro-N-nitrosoguanidine) acts on polynucleotides in neutral aqueous solution, methylating guanine in the 7-position, and, to a much lesser extent, adenine. In 67 percent dimethylformamide the effect on the purines decreased, and what seems to be 3-methyl-cytosine appeared. In formamide solution no base changes were detected. Nitrosoguanidine had little mutagenic effect on tobacco mosaic virus RNA in water; it had greater effect in dimethylformamide, and even greater in formamide; it was a strong mutagen only when it acted on intact tobacco mosaic virus particles. Thus, neither the methylation of guanine nor the cytosine modification represents the main mutagenic event.