Detection method based on signal-amplified DNA cascade reaction with target extension

摘要

Methods, compositions and kits for detecting a target nucleic acid in a sample. The method comprises a first signal DNA generating sequence, an endonuclease recognition site, and a sequence complementary to the 3 ′ end of the target nucleic acid in the 5 ′ to 3 ′ direction in the presence of a polymerase and an endonuclease. A second oligonucleotide comprising, in 5 ′ to 3 ′ direction, a second signal DNA generating sequence, an endonuclease recognition site, and a sequence homologous to the first signal DNA generating sequence of the first oligonucleotide In a 5 ′ to 3 ′ direction, a third oligonucleotide and sample comprising a sequence homologous to the third signal DNA generating sequence, the endonuclease recognition site, and the second signal DNA generating sequence of the second oligonucleotide. Including contacting. The reaction causes a signal cascade. The polymerase preferably has strand displacement activity, and the target nucleic acid is preferably microRNA.