Single mRNA Imaging with Fluorogenic RNA Aptamers and Small‐molecule Fluorophores

Abstract

Messenger RNA (mRNA) is the fundamental information transfer system in the cell. Tracking single mRNA from transcription to degradation with fluorescent probes provides spatiotemporal information in cells about how the genetic information is transferred from DNA to proteins. The traditional single mRNA imaging approach utilizes RNA hairpins (e.g. MS2) and tethered fluorescent protein as probes. As an exciting alternative, RNA aptamers: smallmolecule fluorophores (SFs) systems have emerged as novel single mRNA imaging probes since 2019, exhibiting several advantages including fluorogenic ability and minimal perturbation. This review summarizes all five reported RNA aptamers: SFs systems for single mRNA imaging in living cells so far. It also discusses the challenges and provides prospects for single mRNA imaging applications. This review is expected to inspire researchers to develop RNA aptamers: SFs systems for studying gene expression at single-molecule resolution in cells.

Toehold-Mediated Shape Transition of Nucleic Acid Nanoparticles

“…The fluorogenic RNA aptamers, also known as “light-up” aptamers, activate small fluorophore molecules upon binding. , These reporters have shown some advantages over other imaging techniques such as FRET, FISH, and molecular beacons. , While the latest methods are limited to only exogenously introduced NANPs, the fluorescent dyes must be covalently linked to either the 5′- or 3′-end of nucleic acids, and the light-up RNA aptamers offer excellent real-time imaging that is label-free, protein-free, has a high signal-to-noise ratio, and possess modularity for simple sequence incorporation and tagging. ,− This opens endless possibilities to program functional NANPs and nucleic acid nanodevices for logical operation in vitro and in vivo. − …”

Signal “On-Amplified-Off” Strategy Based on Hafnium Dioxide Nanomaterials as Electrochemiluminescence Emitters for Progesterone Detection

“…Aptamers are short oligonucleotide sequences that are screened in vitro to specifically bind to target molecules such as proteins or small molecules. , They offer advantages over antibodies, including simple chemical synthesis or modification, high stability, easy storage, and a wide range of target recognition. , Their high affinity and selectivity render them ideal for numerous applications, including cell imaging, disease treatment, and biosensor analysis. − An electrochemiluminescence (ECL) aptasensor, created by combining an aptamer as a recognition module with the ECL technology, offers superior sensitivity, low background signal, simple operation, and rapid analysis. , An ECL aptasensor typically immobilizes the aptamer onto an electrode surface and employs a luminescent molecule to label it. The emergence of the ECL aptasensor has immensely enhanced the sensitivity and specificity of analyzing small molecular targets such as toxins, antibiotics, and hormones. − …”