Synthetic biological approaches for RNA labelling and imaging: design principles and future opportunities

- Contemporary strategies for site-specific labelling of RNA are described.
- Non-natural nucleotides offer opportunities to install functional groups at defined sites within RNA molecules.
- Fluorogenic aptamer technology enables the visualization of unmodified RNA.
- CRISPR-Cas9 technology enables direct imaging of RNA in cells, dispelling the need to engineer target RNA molecules.

RNA is the most mercurial of all biomacromolecules. In contrast to DNA, where the predominant role is the storage of genetic information, the biological role of RNA varies; ranging from a template-based intermediary in gene expression to playing a direct role in catalysis. Their high turnover and metabolic lability makes the detection of specific sequences particularly challenging. This review describes the latest synthetic biological developments that enable the direct imaging of RNA both in vitro and in their native cellular environment.

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