Nonionic oligonucleotides

Abramova, T.V., Vorob ev, Yu. N., and Lebedev, A V. (1986) Investigations of diastereomers of nonionic oligonucleotide analogues. IV. Influence of configuration at asymmetric phosphorus atoms in ethyl esters of deoxyoligothy-midylate on the stability of their complexes with poly(dA). Bioorg. Khim 12, 1335-1347... 

Nonionic oligonucleotide analogs have attracted much interest in recent years as potential candidates for oligonucleotide-based therapeutics. Compared to their natural parent molecules, they are expected to have the advantage of ... 

Pluronic-g- polyethyleneimine (Pluronic-g-PEI) Graft-copolymer, branched PEI segment grafted with nonionic triblock copolymer In vitro and in vivo transfections and oligonucleotide delivery (Nguyen etal., 2000)... 

Mixed backbone hybrid oligonucleotides also have been made using methylphosphonate iinkages at the ends. Methyiphosphonates are nonionic, are resistant to nucleases, but do not lead to RNase H degradation. The reduced polyanionic nature of the mixed backbone oligonucleotide with methylphosphonate moieties have the potential to reduce the clotting abnormality associated with the use of phosphorothioate agents (14). 

The nonionic methylphosphonates fulfill these requirements. Studies have been carried out on methylphosphonate oligonucleotides for more than 20 years originating with the pioneering work of Ts o and Miller (4,5). Methylphosphonates have shown sequence-specific inhibition of translation, are taken into cells readily, and have a minimum of toxicity (4-12). In addition, methylphosphonates have been shown to form triple strands with DNA targets (13). 

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