Patent ID: 7354708

Claim:
A method of detecting a target polynucleotide which comprises the steps of: a) contacting a target polynucleotide having a first portion and a second portion immediately contiguous to one another with: i) an invader oligonucleotide, at least a part of which is capable of specifically hybridizing to the first portion of the target polynucleotide; ii) a first probe oligonucleotide comprising a first region that is capable of specifically hybridizing to the second portion of the target polynucleotide and an unpaired region located adjacent to the first region; and iii) a reagent that is capable of cleaving to release the unpaired region of the first probe oligonucleotide to produce a cleaved unpaired region, wherein said reagent comprises a 5â€² nuclease; producing said cleaved unpaired region by cleaving said first probe oligonucleotide, forming a cleavage structure comprising said cleaved unpaired region and a second probe oligonucleotide by hybridizing said cleaved unpaired region to said second probe oligonucleotide, or forming a cleavage structure comprising said cleaved unpaired region, said second probe oligonucleotide, and a target nucleic acid by hybridizing said cleaved unpaired region and said second probe oligonucleotide to said target nucleic acid, and generating a cleaved second probe by cleaving said second cleavage structure using the reagent; b) detecting the accumulation of the cleaved second probe oligonucleotide; and c) determining whether the cleaved second probe oligonucleotide accumulates exponentially over time, wherein said exponential accumulation of the cleaved second probe oligonucleotide over time is indicative of the presence of said target polynucleotide.