DETECTION OF NUCLEIC ACIDS BY FLOURESCENCE QUENCHING

摘要

Detector nucleic acids are employed for detection of nucleic acid target seq uences by fluorescence quenching mechanisms. The detector nucleic acid comprises at le ast two oligonucleotides and is partially single-stranded and partially double-stran ded. One of the two dyes of a donor/acceptor dye pair is linked to the first oligonucleotide and the other is linked to a second oligonucleotide such that they are in close spatial proximity when the first and second oligonucleotides are base-paired and donor fluorescence is quenched. A singl e second oligonucleotide may be hybridized to the first oligonucleotide or multiple s econd oligonucleotides may be hybridized to the first oligonucleotide and to each other, forming a junction structure comprising multiple donor/acceptor dye pairs. The detecto r oligonucleotide retains its partially single-stranded and partially double-stranded conforma tion in the absence of target. In the presence of target, however, the second oligonucleotide(s) of the detector nucleic acid is/are completely or partially displaced from the first, increa sing the distance between the donor and acceptor dyes and causing a change in fluorescence whi ch may be detected as an indication of the presence of the target sequence.