Tail-labelling of DNA probes using modified deoxynucleotide triphosphates and terminal deoxynucleotidyl tranferase. Application in electrochemical DNA hybridization and protein-DNA binding assays
作者:Petra Horáková、Hana Macíčková-Cahová、Hana Pivoňková、Jan Špaček、Luděk Havran、Michal Hocek、Miroslav Fojta
DOI:10.1039/c0ob00856g
日期:——
A simple approach to DNA tail-labelling using terminal deoxynucleotidyl transferase and modified deoxynucleoside triphosphates is presented. Amino- and nitrophenyl-modified dNTPs were found to be good substrates for this enzyme giving 3′-end stretches of different lengths depending on the nucleotide and concentration. 3-Nitrophenyl-7-deazaG was selected as the most useful label because its dNTP was efficiently incorporated by the transferase to form long tail-labels at any oligonucleotide. Accumulation of many nitrophenyl tags per oligonucleotide resulted in a considerable enhancement of voltammetric signals due to the nitro group reduction, thus improving the sensitivity of electrochemical detection of the tail-labelled probes. We demonstrate a perfect discrimination between complementary and non-complementary target DNAs sequences by tail-labelled hybridization probes as well as the ability of tumour suppressor p53 protein to recognize a specific binding site within tail-labelled DNA substrates, making the methodology useful in electrochemical DNA hybridization and DNA-protein interaction assays.
本文介绍了一种使用末端脱氧核苷酸转移酶和修饰的脱氧核苷三磷酸酯进行 DNA 尾部标记的简单方法。研究发现,氨基和硝基苯基修饰的 dNTPs 是该酶的良好底物,根据核苷酸和浓度的不同,可产生不同长度的 3′ 端延伸。3-Nitrophenyl-7-deazaG 被选为最有用的标记,因为它的 dNTP 能被转移酶有效结合,在任何寡核苷酸上形成长尾标记。由于硝基还原,每个寡核苷酸积累了许多硝基苯标签,从而大大增强了伏安信号,提高了尾部标记探针的电化学检测灵敏度。我们展示了尾部标记杂交探针对互补和非互补目标 DNA 序列的完美分辨能力,以及肿瘤抑制因子 p53 蛋白识别尾部标记 DNA 底物中特定结合位点的能力,从而使该方法在电化学 DNA 杂交和 DNA 蛋白相互作用检测中大显身手。