Department of Chemistry, Graduate School of Science , Tohoku University , Japan , Sendai 980-8578 , Japan.
Anal Chem. 2019 Nov 19;91(22):14254-14260. doi: 10.1021/acs.analchem.9b01997. Epub 2019 Oct 18.
RNA-binding small probes with deep-red emission are promising for RNA analysis in biological media without suffering from background fluorescence. Here benzo[,]indole-quinoline (BIQ), an asymmetric monomethine cyanine analogue, was newly developed as a novel RNA-selective probe with light-up signaling ability in the deep-red spectral range. BIQ features a significant light-up response (105-fold) with an emission maximum at 657 nm as well as improved photostability over the commercially available RNA-selective probe, SYTO RNA select. BIQ was successfully applied to the fluorescence imaging of nucleolar RNAs in living cells with negligible cytotoxicity. Furthermore, we found the useful ability of BIQ as a base surrogate integrated in peptide nucleic acid (PNA) oligonucleotides for RNA sequence analysis. BIQ base surrogate functioned as a deep-red light-up base surrogate in forced intercalation (FIT) and triplex-forming FIT (tFIT) systems for the sequence-selective detection of single-stranded and double-stranded RNAs, respectively.
具有深红光发射的 RNA 结合小分子探针在生物介质中进行 RNA 分析时很有前途，因为它们不会受到背景荧光的影响。在这里，苯并[，]吲哚-喹啉（BIQ）是一种新型不对称单甲川菁类染料，是一种新型的 RNA 选择性探针，具有在深红光范围内的点亮信号能力。BIQ 具有显著的点亮响应（105 倍），发射最大值为 657nm，并且比市售的 RNA 选择性探针 SYTO RNA select 的光稳定性更好。BIQ 成功地应用于活细胞中核仁 RNA 的荧光成像，具有可忽略的细胞毒性。此外，我们发现 BIQ 作为一种碱基替代物整合到肽核酸（PNA）寡核苷酸中，在 RNA 序列分析中具有有用的能力。BIQ 碱基替代物在强制嵌入（FIT）和三链形成 FIT（tFIT）系统中作为深红光点亮碱基替代物，分别用于单链和双链 RNA 的序列选择性检测。
