Method for hybridizing nucleic acids

A method for detecting or amplifying a target nucleic acid in a sample of genomic DNA or of total RNA, comprising at least an oligonucleotide-oligocation conjugate Ai-Bj and comprising the steps of:

• extending an oligonucleotide-oligocation conjugate Ai-Bj of structure I to III with said target nucleic acid in a sample of genomic DNA as a template;
• detecting said target nucleic acid in said sample of genomic DNA with an oligonucleotide-oligocation conjugate Ai-Bj of structure I to X;
• or
• reverse transcribing said target nucleic acid of a sample of total RNA with an oligonucleotide-oligocation conjugate Ai-Bj of structure I to III;
• wherein in said conjugate Ai-Bj
• Ai is an i-mer oligonucleotide with i=3 to 50, where Ai is an oligomer with naturally or non naturally occurring nucleobases and/or pentafuranosyl groups and/or native phosphodiester bonds,
• Bj, moiety is attached to Ai moiety or to linker to Ai via a phosphodiester link,
• Bj, being a j-mer organic oligocation moiety, with j=1 to 50, where B is:
• —HPO3—R1—(NH—R2)n—NH—R3—O—, where R1, R2 and R3 identical or different, are a C1-C6 alkylene radical, the NH—R2 moieties being identical or different when n is >1;
• —HPO3—R1—CH(X)—R3—O— where R1 and R3, identical or different, are a C1-C6 alkylene radical and X is putrescine, spermidine or a spermine residue,
• said structures Ito X being as follows:
• HO—3′Ai5′-Bj-R4 structure I
• HO—3′Ai5′-R5—Bj-R4 structure II
• HO—3′Ai15′—Bj-Ai2-R4 structure III
• R4—Bj-3′Ai5′—R6 structure IV
• R4—Bj-R53′Ai5′-R6 structure V
• R7-3′Ai5′-Bj—R4 structure VI
• R7-3′Ai5′-R5—Bj—R4 structure VII
• R7-3′Ai15′-Bj-3′Ai25′-R4 structure VIII
• R7-3′Ai15′-Bj-5′Ai23′-R8 structure IX
• R4—Bj1-3′Ai5′-Bj2-R6 structure X
• wherein
• Ai1 and Ai2, identical or different are i-mer oligonucleotides with i=3 to 50, where Ai1 and Ai2 are oligomers with naturally or non naturally occurring nucleobases and/or pentafuranosyl groups and/or native phosphodiester bonds;
• R4 and R6, identical or different, are H or a linker, a quencher, a marker, a chromophore group, a fluorophore group, a chemical moiety, a biotin, a hydrophobic chain, a cholesterol derivative, an antigen, a protein, a peptide, a sugar group and a phosphate group;
• R5, different from H, Ai and Bj, is a chemically stable or cleavable linker between Ai and Bj;
• R7 and R8, identical or different, are different from H and are selected in the group comprising a linker, a quencher, a marker, a chromophore group fluorophore group, a chemical moiety, a biotin, a hydrophobic chain, a cholesterol derivative, an antigen, a protein, a peptide, a phosphate group and a sugar group.