Preferential reaction of the carcinogen N-acetoxy-2-acetylaminofluorene with satellite DNA

The carcinogens N-acetoxy-2-acetylaminofluorene ( N-acetoxy-AAF) and N-hydroxy-2-aminofluorene ( N-hydroxy-AF) were incubated with calf thymus DNA to determine if reaction occurred preferentially with discrete regions within the DNA. Derivative melting profiles indicated that both compounds decreased satellite transitions and that N-acetoxy-AAF depressed the melting of higher temperature regions. These data suggest that N-acetoxy-AAF reacted to a greater extent with G + C-rich regions and, because the resulting adduct disrupted the helix, the cooperativity of melting decreased. Reaction of N-acetoxy-AAF with purified satellite III DNA confirmed the preferential interaction of this carcinogen with G + C-rich regions as compared to main component DNA. The derivative melting profile of λ DNA in the presence of actinomycin D further demonstrated that this type of analysis can detect preferential interactions with specific DNA sequences.