Tsuda Naoto, Matsumoto Ayumi, Ito Aya, Uneda Tomomi, Tanabe Atsuhiro, Obika Satoshi, Imanishi Takeshi
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
Nucleic Acids Symp Ser (Oxf). 2005(49):335-6. doi: 10.1093/nass/49.1.335.
Antigene strategy is promising technology to regulate gene expression. We have previously reported that 2'-O,4'-C-methylene bridged nucleic acid (2',4'-BNA) modification of triplex-forming oligonucleotides (TFOs) significantly enhanced the binding affinity towards the target dsDNA. In spite of its usefulness, the TFO-binding site may not completely overlay the protein-binding site because of the limitation of TFOs targeting sequences. To overcome this problem, we developed an antigene-based new methodology called "antigene-block" strategy. In this methodology, the TFOs bearing a bulky hairpin tail are used for efficient inhibition of protein-DNA interaction. The antigene-block TFOs having 2',4'-BNA modifications formed stable triplexes with the homopurine-homopyrimidine sequence which partially overlap the transcription factor NF-kappaB binding site. In addition, the antigene-block TFOs significantly reduced the expression level of the target-gene in living cells, while conventional 2',4'-BNA-modified or unmodified TFOs showed no effect on the target-gene expression.
反基因策略是一种很有前景的调控基因表达的技术。我们之前报道过，对三链形成寡核苷酸（TFOs）进行2'-O,4'-C-亚甲基桥连核酸（2',4'-BNA）修饰可显著增强其与靶双链DNA的结合亲和力。尽管它很有用，但由于TFOs靶向序列的局限性，TFO结合位点可能无法完全覆盖蛋白质结合位点。为克服这一问题，我们开发了一种基于反基因的新方法，称为“反基因阻断”策略。在这种方法中，带有庞大发夹尾巴的TFOs用于有效抑制蛋白质-DNA相互作用。具有2',4'-BNA修饰的反基因阻断TFOs与同型嘌呤-同型嘧啶序列形成稳定的三链体，该序列与转录因子NF-κB结合位点部分重叠。此外，反基因阻断TFOs显著降低了活细胞中靶基因的表达水平，而传统的2',4'-BNA修饰或未修饰的TFOs对靶基因表达没有影响。
