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  2. Living-Cell MicroRNA Imaging with Self-Assembling Fragments of Fluorescent Protein-Mimic RNA Aptamer

Living-Cell MicroRNA Imaging with Self-Assembling Fragments of Fluorescent Protein-Mimic RNA Aptamer

  • ACS Sens. 2021 Jun 25;6(6):2339-2347. doi: 10.1021/acssensors.1c00453.
Yu Gu 1 2 Li-Juan Huang 3 Wei Zhao 3 Ting-Ting Zhang 3 Mei-Rong Cui 3 Xue-Jiao Yang 3 Xue-Li Zhao 4 Hong-Yuan Chen 3 Jing-Juan Xu 3
Affiliations

Affiliations

  • 1 State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
  • 2 Institute for Materials Science and Engineering, School of Materials Sciences and Engineering, Suzhou University of Science and Technology, Suzhou 215011, China.
  • 3 State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
  • 4 College of Chemistry and Molecular Engineering, Zheng-Zhou University, Zhengzhou 450001, China.
Abstract

As the cellular roles of RNA abundance continue to increase, there is an urgent need for the corresponding tools to elucidate native RNA functions and dynamics, especially those of short, low-abundance RNAs in live cells. Fluorescent RNA Aptamers provide a useful strategy to create the RNA tag and biosensor devices. Corn, which binds with 3,5-difluoro-4-hydroxybenzylidene-imidazolinone-2-oxime (DFHO), is a good candidate for the RNA tag because of its enhanced photostability and red-shifted spectrum. Herein, we report for the first time the utilization of Corn as a split aptamer system, combined with RNA-initiated fluorescence complementation (RIFC), for monitoring RNA self-assembly and sensing MicroRNA. In this platform, the 28-nt Corn was divided into two nonfunctional halves (named probe I and probe II), and an additional target RNA recognition and stem part was introduced in each probe. The target RNA can trigger the self-assembly reconstitution of the Corn's G-quadruplex scaffold for DFHO binding and turn-on fluorescence. These probes can be transfected stably into mammalian cells and deliver the light-up fluorescent response to microRNA-21 (miR-21). Significantly, the probes have good photostability, with minimal fluorescence loss after continuous irradiation, and can be used for imaging of miR-21 in living mammalian cells. The proposed method is universal and could be applied to the sensing of other tumor-associated RNAs, including messenger RNA and noncoding RNA, as well as for monitoring RNA/RNA interactions. The Corn-based splitting Aptamers show promising potential in the real-time visualization and mechanistic analysis of nucleic acids.

Keywords

G-quadruplexes; RNA aptamers; RNA-initiated fluorescence complementation; microRNA imaging; self-assembling.

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