Rossetti Luigi, D'Isa Giuliana, Mauriello Clementina, Varra Michela, De Santis Pasquale, Mayol Luciano, Savino Maria
Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, Piazzale Aldo Moro, 5, c.a.p. 00185, Roma, Italy.
Biophys Chem. 2007 Aug;129(1):70-81. doi: 10.1016/j.bpc.2007.05.009. Epub 2007 May 21.
The promoter of human telomerase reverse transcriptase (hTERT) gene, in the region from -1000 to +1, contains two homopurine-homopyrimidine sequences (-835/-814 and -108/-90), that can be considered as potential targets to triple helix forming oligonucleotides (TFOs) for applying antigene strategy. We have chosen the sequence (-108/-90) on the basis of its unfavorable chromatin organization, evaluated by theoretical nucleosome positioning and nuclease hypersensitive sites mapping. On this sequence, anti-parallel triplex with satisfactory thermodynamic stability is formed by two TFOs, having different lengths. Triplex stability is significantly increased by specific interactions with the perylene derivative N,N'-bis[3,3'-(dimethylamino) propylamine]-3,4,9,10-perylenetetracarboxylic diimide (DAPER). Since DAPER is a symmetric molecule, the induced Circular Dichroism (CD) spectra in the range 400-600 nm allows us to obtain information on drug binding to triplex and duplex DNA. The drug-induced ellipticity is significantly higher in the case of triplex with respect to duplex and, surprisingly, it increases at decreasing of DNA. A model is proposed where self-stacked DAPER binds to triplex or to duplex narrow grooves.
人端粒酶逆转录酶（hTERT）基因的启动子，在-1000至+1区域内，包含两个同型嘌呤-同型嘧啶序列（-835/-814和-108/-90），可被视为三链螺旋形成寡核苷酸（TFO）应用反基因策略的潜在靶点。我们基于其不利的染色质组织（通过理论核小体定位和核酸酶超敏位点作图评估）选择了序列（-108/-90）。在该序列上，由两个不同长度的TFO形成了具有令人满意的热力学稳定性的反平行三链体。通过与苝衍生物N,N'-双[3,3'-（二甲氨基）丙胺]-3,4,9,10-苝四羧酸二酰亚胺（DAPER）的特异性相互作用，三链体稳定性显著提高。由于DAPER是对称分子，在400-600nm范围内诱导的圆二色性（CD）光谱使我们能够获得有关药物与三链体和双链体DNA结合的信息。与双链体相比，三链体情况下药物诱导的椭圆率明显更高，而且令人惊讶的是，随着DNA的减少它会增加。提出了一个模型，其中自堆积的DAPER与三链体或双链体的窄沟结合。
