Modified nucleic acid probes and use thereof

Abstract

Disclosed is a method of detecting a nucleic acid sequence of interest in a sample, the method comprising contacting the sample with first and second probes; the first probe comprising a portion complementary to the sequence of interest and so capable of hybridising thereto, and a portion non-complementary to the sequence of interest; the second probe comprising a portion complementary to the sequence of interest and so capable of hybridising thereto, and a portion non-complementary to the sequence of interest but complementary to that portion of the first probe which is non-complementary to the sequence of interest, such that the first and second probes are capable of hybridising to the sequence of interest in an adjacent or substantially adjacent manner, so as to allow complementary portions of the first and second probes to hybridize to each other; causing extension of the first probe with a nucleic acid polymerase, using the second probe as a template; and detecting directly or indirectly the extension of the first probe, so as to indicate the presence of the sequence of interest; characterised in that the first and/or second probe comprises a destabilizing moiety which cannot base pair with the reciprocal probe, thereby preventing hybridisation of the first and second probes in the absence of the sequence of interest.