DNA sequence-enabled reassembly of the green fluorescent protein

We describe a general methodology for the direct detection of DNA by the design of a split-protein system that reassembles to form an active complex only in the presence of a targeted DNA sequence. This approach, called SEquence Enabled Reassembly (SEER) of proteins, combines the ability to rationally dissect proteins to construct oligomerization-dependent protein reassembly systems and the availability of DNA binding Cys₂-His₂ zinc-finger motifs for the recognition of specific DNA sequences. We demonstrate the feasibility of the SEER approach utilizing the split green fluorescent protein appended to appropriate zinc fingers, such that chromophore formation is only catalyzed in the presence of DNA sequences that incorporate binding sites for both zinc fingers.