The present invention relates to intercalator pseudonucleotides. Intercalator pseudonucleotides according to the invention are capable of being incorporated into the backbone of a
nucleic acid or
nucleic acid analogue and they comprise an intercalator comprising a flat
conjugated system capable of co-stacking with nucleobases of
DNA. The invention also relates to oligonucleotides or
oligonucleotide analogues comprising at least one intercalator pseudo
nucleotide. The invention furthermore relates to methods of synthesising intercalator pseudo nucleotides and methods of synthesising oligonucleotides or
oligonucleotide analogues comprising at least one intercalator pseudonucleotide. In addtition, the invention describes methods of separating sequence specific
DNA(s) from a mixture comprising nucleic acids, methods of detecting a sequence specific
DNA (target DNA) in a mixture comprising nucleic acids and / or
nucleic acid analogues and methods of detecting a sequence specific
RNA in a mixture comprising nucleic acids and / or nucleic acid analogues. In particular said methods may involve the use of oligonucleotides comprising intercalator pseudo nucleotides. The invention furthermore relates to pairs of oligonucleotides or
oligonucleotide analogues capable of hybridising to one another, wherein said pairs comprise at least one intercalator pseudonucleotide. Methods for inhibiting a DNAse and / or a RNAse and methods of modulating transcription of one or more specific genes are also described.