G-quadruplexes (G4s), the noncanonical nucleic acid secondary structure, form within guanine-rich DNA or RNA sequences. G4s formation can affect chromatin architecture and gene regulation and has been associated with various cellular functions, including DNA replication, transcription, and genome maintenance. Visualizing and detecting G4s precisely in such processes is essential to increasing our understanding of G4s biology. Considerable attention has focused on the G4s targeting molecular imaging studies. Besides, fluorescent light-up aptamers (FLAPs, also referred to as fluorogenic aptamers) have gained momentum, which commonly have a G4 scaffolding for imaging intracellular RNAs and metabolites. In this review, we first introduce several representative fluorescent imaging approaches for tracking G4s in cells and in vivo. We also discuss the potential of G4-containing FLAPs in bioimaging and summarize current developments in this field from the standpoint of fluorescent molecules. Finally, we discuss the present challenges and future potential of G4 imaging and G4-containing FLAPs development.

中文翻译：

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基于 G-四链体的荧光成像的进展

G-四链体 (G4s) 是一种非规范核酸二级结构，在富含鸟嘌呤的 DNA 或 RNA 序列中形成。G4s 的形成可以影响染色质结构和基因调控，并与多种细胞功能相关，包括 DNA 复制、转录和基因组维护。在这些过程中精确地可视化和检测 G4s 对于增加我们对 G4s 生物学的理解至关重要。相当多的注意力集中在针对分子成像研究的 G4 上。此外，荧光发光适体（FLAP，也称为荧光适体）获得了发展势头，通常具有 G4 支架，用于对细胞内 RNA 和代谢物进行成像。在这篇综述中，我们首先介绍了几种具有代表性的荧光成像方法，用于跟踪细胞中的 G4 和体内。我们还讨论了含有 G4 的 FLAP 在生物成像中的潜力，并从荧光分子的角度总结了该领域的当前发展。最后，我们讨论了 G4 成像和包含 G4 的 FLAP 开发的当前挑战和未来潜力。