New Two-Component Pyrene Probes Based on Oligo(2'- O -Methylribonucleotides) for microRNA Detection

New two-component pyrene probes based on oligo(2'- O -methylribonucleotides) for microRNA detection have been designed. They contain the Py A-modified adenine cluster (pentaadenosine fragment that contains 8-(1-ethynylpyrene)-deoxyriboadenosine in the center) and can form a three-way junction (3WJ) structure with a target RNA. We have chosen microRNA let-7a-3p as the RNA target because of the correlation of its concentration in cells with the appearance and progression of cancer. We have compared the thermal stability and fluorescence properties of the two-component probes based on oligo(2'- O -methylribonucleotides) that contain either deoxyriboadenosine (dAdA Py AdAdA) or the (2'- O -methylribo)adenosine (A m A m Py AA m A m ) cluster with those of (dAdA Py AdAdA)-containing oligodeoxyribonucleotide. The changes in the fluorescence spectra of two-component probes after hybridization with the RNA target have been demonstrated. These probes can be used for designing a new microRNA detection system.