University of North Carolina at Chapel Hill / Antonio L. Amelio*
Fluorescent proteins are widely used to study molecular and cellular events, yet this traditionally relies on delivery of excitation light, which can trigger autofluorescence, photoxicity, and photobleaching, impairing their use in vivo. Accordingly, chemiluminescent light sources such as those generated by luciferases have emerged, as they do not require excitation light. However, current luciferase reporters lack the brightness needed to visualize events in deep tissues. We report the creation of chimeric eGFP-NanoLuc (GpNLuc) and LSSmOrange-NanoLuc (OgNLuc) fusion reporter proteins coined LumiFluors, which combine the benefits of eGFP or LSSmOrange fluorescent proteins with the bright, glow-type bioluminescent light generated by an enhanced small luciferase subunit (NanoLuc) of the deep-sea shrimp Oplophorus gracilirostris. The intramolecular bioluminescence resonance energy transfer that occurs between NanoLuc and the fused fluorophore generates the brightest bioluminescent signal known to date, including improved intensity, sensitivity, and durable spectral properties, thereby dramatically reducing image acquisition times and permitting highly sensitive in vivo imaging. Notably, the self-illuminating and bifunctional nature of these LumiFluor reporters enables greatly improved spatiotemporal monitoring of very small numbers of tumor cells via in vivo optical imaging and also allows the isolation and analyses of single cells by flow cytometry. Thus, LumiFluor reporters are inexpensive, robust, noninvasive tools that allow for markedly improved in vivo optical imaging of tumorigenic processes. Cancer Res; 75(23); 5023-33.
Schaub FX1, Reza MS2, Flaveny CA3, Li W1, Musicant AM4, Hoxha S5, Guo M2, Cleveland JL1, Amelio AL6.
1 Department of Tumor Biology, Moffitt Cancer Center and Research Institute, Tampa, Florida.
2 Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida.
3 Department of Pharmacological & Physiological Science, School of Medicine, Saint Louis University, St. Louis, Missouri.
4 UNC Biological and Biomedical Sciences Graduate Program, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
5 Scripps Graduate Program, The Scripps Research Institute, Scripps Florida, Jupiter, Florida.
6 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. email@example.com.