Both enrichment and fluorogenic labelling of 5-formyluracil in DNA
Recently, the detection of the natural thymine modification 5-formyluracil has attracted widespread attention. Herein, we put forward a new insight into designing reagents for both selective biotin enrichment and fluorogenic labelling of 5-formyluracil in DNA. Biotinylated o-phenylenediamine directly tethered to naphthalimide can switch on 5-formyluracil under physical conditions that can be used in cell imaging after exposure to γ-irradiation. In addition, its labelling property caused the polymerase extension to stop in the 5-formyluracil site, which gave us more information than did the fluorescence itself. The idea of detecting 5-formyluracil might be used in the synthesis of other modified diaminofluoresceins.