[en] Using [32P]DNA alkylated with [3H]methyl methanesulfonate, depurinated by heating at 50 degrees C for various periods, then treated with sodium hydroxide, a table was constructed giving the DNA fraction soluble in 5% perchloric acid at 0 degree C as a function of the frequency of strand breaks. The alkaline treatment placed a break near each apurinic site; the apurinic sites were counted in two ways which gave consonant results: by the loss of [3H]methyl groups and by reaction with [14C]methoxyamine. The 32P label of DNA was used to measure the acid-solubility.
Disciplines :
Human health sciences: Multidisciplinary, general & others
We thank Dr. S. Facchetti of Ispra, who made the mass-spectrometer analyses for us. M.L. was a C.E.C. fellow. The work was supported by grants from the Fonds Beige de la Recherche Fondamen-tale Collective, the Fonds Canc6rologique de la C.G.E.R., and the Direction Biology, Radiation Protection and Medical Research, DG XII, C.E.C. This publication is contribution 2193 of the Pro- gramme Biology, Radiation Protection and Medical Research, Directorate General XII for Research, Science and Education of the Commission of the European Communities.
