Oligonucleotide-polyamine conjugation

Using an easy and versatile procedure for oligonucleotide-polyamine conjugation [46], polyamines were conjugated to distinct terminal and internal positions along nucleotide sequences. Upon poly amine attachment to terminal nucleosides, the hybridization efficiency with the complementary nucleotide sequence increased with the number of cationic amines. However, tethering to an internal nucleoside resulted in a considerable decrease in duplex stabihty. However, in phosphorothioates... 

Winkler J, Saadat K, Gavilan MD, Urban E, Noe CR (2009) Oligonucleotide-polyamine conjugates influence of length and position of 2 -attached polyamines rat duplex stability and antisense effect. Eur J Med Chem 44 670-677... 

Incorporation of an anthraquinone moiety, attached through an acyclic backbone unit, into a duplex DNA such that the anthraquinone was opposed to 5-methyl-dC resulted in an efficient one-electron oxidation to 5-formyl-dC or 5-hydroxymethyl-dC. Treatment of the duplex with hot piperidine led to strand-specific cleavage at the oxidised cytosine base. An anthraquinone has been used to link chimeric a-p oligonucleotides for formation of alternate-stranded triplexes. The two oligonucleotides were linked through a substituted propionic acid derivative which was further conjugated to the anthraquinone via various polyamines. 

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