Engineering of a fluorescent chemogenetic reporter with tunable color for advanced live-cell imaging

Fluorescent reporters spanning the visible spectrum are needed for imaging live cells and organisms. Here the authors report a collection of fluorogenic chromophores that cover the visible spectrum from blue to red using a single engineered and optimised protein tag. Biocompatible fluorescent reporters with spectral properties spanning the entire visible spectrum are indispensable tools for imaging the biochemistry of living cells and organisms in real time. Here, we report the engineering of a fluorescent chemogenetic reporter with tunable optical and spectral properties. A collection of fluorogenic chromophores with various electronic properties enables to generate bimolecular fluorescent assemblies that cover the visible spectrum from blue to red using a single protein tag engineered and optimized by directed evolution and rational design. The ability to tune the fluorescence color and properties through simple molecular modulation provides a broad experimental versatility for imaging proteins in live cells, including neurons, and in multicellular organisms, and opens avenues for optimizing Forster resonance energy transfer (FRET) biosensors in live cells. The ability to tune the spectral properties and fluorescence performance enables furthermore to match the specifications and requirements of advanced super-resolution imaging techniques.

Automated summary

Fluorescent reporters covering the visible spectrum are essential for imaging living cells and organisms. The authors have developed a collection of fluorogenic chromophores spanning from blue to red using a single engineered protein tag. This tool allows for tuning fluorescence color and properties, providing versatility for imaging proteins in live cells and optimizing FRET biosensors.