基于核酸脱碱基位点的铽离子荧光增强型单核苷酸多态性识别研究

Study on Recognition of Single-nucleotide Polymorphism based on Fluorescence Enhancement of Terbium Ion upon Binding at an Abasic Site in DNA

基于核酸脱碱基(AP)位点构建了无机配体稀土铽离子(Tb3+)荧光增强型单核苷酸多态性(SNP)识别方法.在目标链靶标碱基对应的探针链上相应位置引入AP位点,发现Tb3+可以选择性地结合在AP位点,光激发时发生从DNA碱基到结合的Tb3+的能量转移,使Tb3+特征荧光显著增强.这种荧光增强作用与靶标碱基及AP位点侧翼碱基类型密切相关.当靶标碱基和侧翼碱基为G时,荧光最强.该方法可用于区分肿瘤抑制基因p53密码子177位的C/G碱基变异.

Recognition of single-nucleotide polymorphism（SNP） was proposed in this work on the basis of fluorescence enhancement of an inorganic ligand,terbium ion（Tb3＋）,upon binding at an abasic（AP） site in DNA.The AP site was deliberately introduced in a probe strand just opposite the base of interest in a target strand.Selective binding of Tb3＋ at the AP site was found by observations of its characteristic fluorescence enhancement for AP site-containing DNA by comparison with fully matched DNA without the AP site.The enhancement is very dependent on the target base and the bases flanking the AP site.When the target base is G,the maximum enhancement of Tb3＋ fluorescence can be obtained especially for guanines flanking the AP site.This method was successfully applied in detection of P177R mutation of codon 177 in cancer repression gene p53,manifesting its potential applications in SNP detection with signal-on fashion.