Structure-specific DNA cleavage on surfaces.

The structure-specific invasive cleavage reaction is a useful means for sensitive and specific detection of single nucleotide polymorphisms, or SNPs, directly from genomic DNA without a need for prior target amplification. A new approach integrating this invasive cleavage assay and surface DNA array technology has been developed for potentially large-scale SNP scoring in a parallel format. Two surface invasive cleavage reaction strategies were designed and implemented for a model SNP system in codon 158 of the human ApoE gene. The upstream oligonucleotide, which is required for the invasive cleavage reaction, is either co-immobilized on the surface along with the probe oligonucleotide or alternatively added in solution. The ability of this approach to unambiguously discriminate a single base difference was demonstrated using PCR-amplified human genomic DNA. A theoretical model relating the surface fluorescence intensity to the progress of the invasive cleavage reaction was developed and agreed well with experimental results.