Musso M, Van Dyke M W
Department of Tumor Biology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Mol Cell Biochem. 1996 Jan 12;154(1):65-70. doi: 10.1007/BF00248462.
A potentially powerful pharmacological approach to modulating the expression of specific, disease-related genes involves the inhibition of transcription factor binding to promoter or enhancer elements through oligonucleotide-mediated triple-helix formation. In vivo, the typical target for intermolecular triplex formation would most likely be torsionally-strained rather than relaxed duplex DNA. To determine the effects of strained DNA on triplex formation, we investigated the interactions between a G/T-rich oligonucleotide and both supercoiled and relaxed plasmid DNA using a restriction endonuclease protection assay. Both the kinetics of formation and dissociation of purine-motif triplexes were unaffected by the conformational state of the duplex DNA. Similarly, the topological state of the plasmid targets was not affected by triplex formation. Taken together, these observations suggest that stable intermolecular triplexes can form in vivo under conditions of moderate torsional strain.
一种潜在的、用于调节特定疾病相关基因表达的强大药理学方法，涉及通过寡核苷酸介导的三链体形成来抑制转录因子与启动子或增强子元件的结合。在体内，分子间三链体形成的典型靶标很可能是扭转应变的双链DNA，而非松弛的双链DNA。为了确定应变DNA对三链体形成的影响，我们使用限制性内切酶保护试验，研究了富含G/T的寡核苷酸与超螺旋和松弛质粒DNA之间的相互作用。嘌呤基序三链体形成和解离的动力学均不受双链DNA构象状态的影响。同样，质粒靶标的拓扑状态也不受三链体形成的影响。综上所述，这些观察结果表明，在适度扭转应变条件下，体内可形成稳定的分子间三链体。
