A method for detecting an miRNA target, comprising: a) providing: i) a sample suspected of containing said miRNA target; ii) a first oligonucleotide that comprises a first portion that is complementary to a region of said miRNA target and a second portion that is not complementary to said miRNA target; iii) a second oligonucleotide that comprises a first portion that is identical in sequence to a second region of said miRNA target and a second portion that lacks sequence identity to said second region of said miRNA target; iv) a reverse transcriptase; v) a DNA polymerase; vi) a FEN-1 endonuclease of an archaebacterial species; vii) a probe oligonucleotide, wherein at least a portion of said probe oligonucleotide is complementary to at least a portion of said miRNA target; and viii) a stacker oligonucleotide comprising a 5' portion, wherein said 5' portion of said stacker oligonucleotide is complementary to a region in said second portion of said first oligonucleotide adjacent to the portion of said first oligonucleotide that is complementary to said miRNA; b) incubating components (i) through (viii) together under conditions such that a detection structure forms, wherein under said conditions: - said reverse transcriptase and said first oligonucleotide are used to reverse transcribe said miRNA to form a miRNA cDNA target which is further - amplified by said first oligonucleotide and said second oligonucleotide and said DNA polymerase in a polymerase chain reaction and - said first oligonucleotide and said probe oligonucleotide hybridize to said amplified cDNA target to form an invasive cleavage structure; and c) detecting said detection structure by cleaving said invasive cleavage structure by said FEN-1 endonuclease and detecting the cleavage of said invasive cleavage structure. a) providing: i) a sample suspected of containing said miRNA target; ii) a first oligonucleotide that comprises a first portion that is complementary to a region of said miRNA target and a second portion that is not complementary to said miRNA target; iii) a second oligonucleotide that comprises a first portion that is identical in sequence to a second region of said miRNA target and a second portion that lacks sequence identity to said second region of said miRNA target; iv) a reverse transcriptase; v) a DNA polymerase; vi) a FEN-1 endonuclease of an archaebacterial species; vii) a probe oligonucleotide, wherein at least a portion of said probe oligonucleotide is complementary to at least a portion of said miRNA target; and viii) a stacker oligonucleotide comprising a 5' portion, wherein said 5' portion of said stacker oligonucleotide is complementary to a region in said second portion of said first oligonucleotide adjacent to the portion of said first oligonucleotide that is complementary to said miRNA; i) a sample suspected of containing said miRNA target; ii) a first oligonucleotide that comprises a first portion that is complementary to a region of said miRNA target and a second portion that is not complementary to said miRNA target; iii) a second oligonucleotide that comprises a first portion that is identical in sequence to a second region of said miRNA target and a second portion that lacks sequence identity to said second region of said miRNA target; iv) a reverse transcriptase; v) a DNA polymerase; vi) a FEN-1 endonuclease of an archaebacterial species; vii) a probe oligonucleotide, wherein at least a portion of said probe oligonucleotide is complementary to at least a portion of said miRNA target; and viii) a stacker oligonucleotide comprising a 5' portion, wherein said 5' portion of said stacker oligonucleotide is complementary to a region in said second portion of said first oligonucleotide adjacent to the portion of said first oligonucleotide that is complementary to said miRNA; b) incubating components (i) through (viii) together under conditions such that a detection structure forms, wherein under said conditions: - said reverse transcriptase and said first oligonucleotide are used to reverse transcribe said miRNA to form a miRNA cDNA target which is further - amplified by said first oligonucleotide and said second oligonucleotide and said DNA polymerase in a polymerase chain reaction and - said first oligonucleotide and said probe oligonucleotide hybridize to said amplified cDNA target to form an invasive cleavage structure; and - said reverse transcriptase and said first oligonucleotide are used to reverse transcribe said miRNA to form a miRNA cDNA target which is further - amplified by said first oligonucleotide and said second oligonucleotide and said DNA polymerase in a polymerase chain reaction and - said first oligonucleotide and said probe oligonucleotide hybridize to said amplified cDNA target to form an invasive cleavage structure; and c) detecting said detection structure by cleaving said invasive cleavage structure by said FEN-1 endonuclease and detecting the cleavage of said invasive cleavage structure.