School of Life Sciences, Central South University, Changsha, 410013, China.
School of Life Sciences, Central South University, Changsha, 410013, China.
Anal Biochem. 2022 Sep 1;652:114775. doi: 10.1016/j.ab.2022.114775. Epub 2022 Jun 3.
MicroRNAs (miRNAs) are commonly used as biomarkers for the diagnosis of tumors. Since miRNA expression is strongly correlated to carcinogenesis, the detection of miRNA concentration in cells would be valuable for the diagnosis and evaluation of tumors. In this study, we proposed a system using two strands of DNA, one modified by a phosphate group at the 5' end, called Cap, and the other with a hairpin structure, called HP. The Cap chain could open the hairpin structure of HP and expose the sequences rich in G bases to form the G-quadruplex structure. Then, a strong fluorescence signal was emitted in the presence of N-methyl mesoporphyrin IX (NMM). However, with the addition of miRNA-21, Cap hybridized with it to form double chains, which were then cleaved by the digestion of lambda exonuclease, resulting in a weak fluorescent signal. The proposed method could detect miRNA-21 at a concentration of 1.4 pM with a broad dynamic linear range from 5 pM to 5 nM.
微 RNA（miRNA）通常被用作肿瘤诊断的生物标志物。由于 miRNA 的表达与致癌作用密切相关，因此检测细胞中 miRNA 的浓度对于肿瘤的诊断和评估将具有重要价值。在本研究中，我们提出了一种使用两条 DNA 链的系统，一条在 5' 端被磷酸基团修饰，称为 Cap，另一条具有发夹结构，称为 HP。Cap 链可以打开 HP 的发夹结构，暴露出富含 G 碱基的序列，形成 G-四链体结构。然后，在存在 N-甲基 mesoporphyrin IX（NMM）的情况下，会发出强烈的荧光信号。然而，随着 miRNA-21 的加入，Cap 与它杂交形成双链，然后被 lambda 外切酶的消化切割，导致荧光信号减弱。该方法可以检测到浓度为 1.4 pM 的 miRNA-21，具有从 5 pM 到 5 nM 的宽动态线性范围。
