Patent ID: 7851150

Claim:
A method for analyzing microRNA, comprising: a) contacting microRNA comprising a 3′ portion comprising a 3′ terminal end and a 5′ portion comprising a 5′ terminal end with a first hairpin probe and a second hairpin probe to form an RNA detection structure, wherein i) said first hairpin probe comprises a 3′ region that is complementary said 3′ portion of said microRNA, and a 5′ region that is not complementary to said microRNA, wherein a first portion of said 5′ region is complementary to a second portion of said 5′ region, wherein said first portion and said second portion of said 5′ region hybridize to each other to form a first duplex when said hairpin probe is hybridized to said microRNA, and wherein said first duplex and said 3′ region of said probe are within one nucleotide of each other; and ii) said second hairpin probe comprises a 5′ region that is complementary to said 5′ portion of said microRNA and a 3′ region that is not complementary to said microRNA, wherein a first portion of said 3′ region is complementary to a second portion of said 3′ region, wherein said first portion and said second portion of said 3′ region hybridize to each other to form a second duplex when said hairpin probe is hybridized to said microRNA, and wherein said second duplex and said 5′ region of said probe are within one nucleotide of each other; wherein, in said RNA detection structure, said microRNA and said first and second hairpin probes form a dumbbell structure, b) detecting formation of said RNA detection structure, wherein formation of said RNA detection structure is indicative of the presence of said microRNA.