Zhang Jiahui, Liang Jihai, Ji Dongsheng, Shu Bing, Huang Zhi-Shu, Li Ding
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou University City, 132 Wai Huan East Road, Guangzhou 510006, P. R. China.
School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, P. R. China.
ACS Sens. 2025 May 23;10(5):3692-3703. doi: 10.1021/acssensors.5c00617. Epub 2025 Apr 28.
The i-motif structure has received increasing interest due to its significant biological function discovered in recent years. However, the absence of a handy and efficient method for visualizing the i-motif limited its intracellular study. Herein, we report an innovative coumarin-carbazole-based fluorescent probe, , for intracellular detection of i-motif. exhibited excellent i-motif recognition ability and selectivity. By using , we successfully visualized the ribosome DNA (rDNA) i-motif within the nucleoli. Our results revealed the colocalization of rDNA i-motif with RNA polymerase I, and their separation under drug-induced nucleolar stress, suggesting that rDNA i-motif could play a regulatory role in rDNA transcription. was also well applied for the detection of the i-motif in live cells and zebrafish juveniles, which could become an important tool for studying its biological function. As we know, this is the first discovery and development of a small-molecule fluorescent probe for specific visualization of i-motif in cells and , providing its direct evidence of participating in key biological function.
近年来，由于i-基序结构具有重要的生物学功能，其受到了越来越多的关注。然而，缺乏一种便捷高效的方法来可视化i-基序限制了其细胞内研究。在此，我们报道了一种基于香豆素-咔唑的新型荧光探针，用于细胞内检测i-基序。该探针表现出优异的i-基序识别能力和选择性。通过使用该探针，我们成功地在核仁内可视化了核糖体DNA（rDNA）i-基序。我们的结果揭示了rDNA i-基序与RNA聚合酶I的共定位，以及它们在药物诱导的核仁应激下的分离，这表明rDNA i-基序可能在rDNA转录中发挥调节作用。该探针也很好地应用于活细胞和斑马鱼幼体中i-基序的检测，这可能成为研究其生物学功能的重要工具。据我们所知，这是首次发现和开发用于特异性可视化细胞内i-基序的小分子荧光探针，为其参与关键生物学功能提供了直接证据。
