Oligonucleotide clamps having diagnostic applications

An oligonucleotide clamp for specifically hybridizing to a target polynucleotide, the oligonucleotide clamp comprising:

• (a) at least one oligonucleotide moiety capable of specifically hybridizing to the target polynucleotide with a Watson-Crick binding component and a Hoogsteen- or a reverse Hoogsteen-binding component;
• or at least two oligonucleotide moieties designated as OL1 and OL2 linked to a hinge region designated as G wherein at least one oligonucleotide moiety has a Watson-Crick binding component and at least one oligonucleotide moiety has a Hoogsteen- or a reverse Hoogsteen-binding component;
• and
• (b) at least one pair of non-oligonucleotide binding moieties, each pair of said binding moieties comprising a first binding moiety and a second binding moiety, the first binding moiety being covalently linked to an oligonucleotide moiety and the second binding moiety being covalently linked to an oligonucleotide moiety, wherein a stable covalent or non-covalent linkage is formed between the first binding moiety and the second binding moiety of the pair when the first and second binding moieties of the pair are brought into juxtaposition by the specific hybridization to the target polynucleotide of at least one or at least two oligonucleotide moieties, wherein said clamp has the formula:
• X--OL1--G--OL2--Y
• wherein:
• OL1 and OL2 are oligonucleotides specific for said target polynucleotide;
• G is a hinge region which links OL1 to OL2 so as to permit specific hybridization of OL1 and OL2 to their respective target polynucleotides;
• and
• X and Y are non-oligonucleotide binding moieties such that X and Y form a stable covalent or non-covalent linkage or complex whenever they are brought into juxtaposition by the hybridization of OL1 and OL2 to said target polynucleotide.