Polycationic copolymers having stabilizing activity toward triplex DNA

核苷酸杂交的稳定化被认为对于使用寡核苷酸改进基因治疗是重要的。我们设计了由聚阳离子主链（聚赖氨酸）和亲水性侧链组成的梳型共聚物作为双螺旋和三螺旋DNA的稳定剂。该共聚物显著提高了三螺旋结构的热稳定性，但不影响三螺旋和单链DNA之间的可逆转变。一个在体外电泳迁移率变动分析表明，共聚物显着增加的Hoogsteen和反向Hoogsteen型三螺旋形成的缔合常数。此外，共聚物的三重螺旋稳定效率显着高于其他寡阳离子，如精胺和亚精胺。它不仅是良好的DNA三螺旋稳定剂，还显示出加速双螺旋DNA与其互补寡核苷酸之间的DNA链交换反应。从这些，我们得出结论，这种共聚物是能够稳定或激活DNA杂交，并可能有用的基因靶向采用寡核苷酸。

Stabilization of nucleotide hybridization is considered important for improving gene therapy using oligonucleotides. We have designed comb-type copolymer consisting of polycation backbone (polylysine) and hydrophilic side chains as a stabilizer for double and triple helical DNAs. The copolymer considerably increased the thermal stability of triple helical structure but did not affect the reversible transition between triple helical and single-stranded DNA. An in vitro electrophoretic mobility shift assay revealed that the copolymer remarkably increased association constants of both Hoogsteen and reverse Hoogsteen-type triple helix formation. Moreover the triple helix-stabilizing efficiency of the copolymer was significantly higher than that of other oligocations like spermine and spermidine. Not only being good DNA triple helix stabilizer, it has also been shown to accelerate DNA strand exchange reactions between double helical DNA and its complementary oligonucleotides. From these, we conclude that this copolymer is capable of either stabilizing or activating DNA hybrids, and may useful for gene targeting employing oligonucleotides.