Poly(L-lysine)-graft-dextran copolymer: amazing effects on triplex stabilization under physiological pH and ionic conditions (in vitro).
Triplex DNA formation involving unmodified triplex-forming oligonucleotides (TFOs) is very unstable under physiological conditions. Here, we report a novel strategy to stabilize both purine and pyrimidine motif triplex DNA within the rat alpha1 (I) collagen gene promoter under physiologically relevant conditions by a poly(L-lysine)- graft -dextran copolymer. Using an in vitro electrophoretic mobility shift assay, we show that the copolymer almost completely abrogates the inhibitory effects of physiological concentrations of monovalent cations, particularly potassium ion (K+), on purine motif triplex formation involving very low concentrations of an unmodified guanine-rich TFO. Of importance, pH dependency in pyrimidine motif triplex formation involving an unmodified cytosine-rich TFO is also significantly overcome by the copolymer. Finally, the triplex-stabilizing efficiency of the copolymer is remarkably higher than that of other oligocations, like spermine and spermidine. We suggest that the ability of the graft copolymer to stabilize triplex DNA under physiologically relevant pH and salt concentrations will be a cue for further progress in the antigene strategy.
Ferdous
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Department of Biomolecular Engineering, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
Watanabe
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H
Akaike
T
T
Maruyama
A
A
D002414:Cations, Monovalent / Q000494:pharmacology; D004247:DNA / Q000737:chemistry* / Q000187:drug effects; D003911:Dextrans / Q000737:chemistry* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation; D011107:Polylysine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011687:Purines / Q000737:chemistry; D012964:Sodium / Q000494:pharmacology; D013095:Spermidine / Q000494:pharmacology; D013096:Spermine / Q000494:pharmacology
D002414:Cations, Monovalent; D003911:Dextrans; D011687:Purines; C113090:poly(lysine)-graft-dextran; C051802:triplex DNA; D011107:Polylysine; D013096:Spermine; D004247:DNA; D012964:Sodium; D011188:Potassium; D013095:Spermidine