Co-reporter:Akira Takai;Kenta Saito;Masahiro Nakano;Remi Haruno;Tatsuya Ohyanagi;Tomonobu M. Watanabe;Takashi Jin;Takeharu Nagai
PNAS 2015 Volume 112 (Issue 14 ) pp:4352-4356
Publication Date(Web):2015-04-07
DOI:10.1073/pnas.1418468112
Fluorescence live imaging has become an essential methodology in modern cell biology. However, fluorescence requires excitation
light, which can sometimes cause potential problems, such as autofluorescence, phototoxicity, and photobleaching. Furthermore,
combined with recent optogenetic tools, the light illumination can trigger their unintended activation. Because luminescence
imaging does not require excitation light, it is a good candidate as an alternative imaging modality to circumvent these problems.
The application of luminescence imaging, however, has been limited by the two drawbacks of existing luminescent protein probes,
such as luciferases: namely, low brightness and poor color variants. Here, we report the development of bright cyan and orange
luminescent proteins by extending our previous development of the bright yellowish-green luminescent protein Nano-lantern.
The color change and the enhancement of brightness were both achieved by bioluminescence resonance energy transfer (BRET)
from enhanced Renilla luciferase to a fluorescent protein. The brightness of these cyan and orange Nano-lanterns was ∼20 times brighter than wild-type
Renilla luciferase, which allowed us to perform multicolor live imaging of intracellular submicron structures. The rapid dynamics
of endosomes and peroxisomes were visualized at around 1-s temporal resolution, and the slow dynamics of focal adhesions were
continuously imaged for longer than a few hours without photobleaching or photodamage. In addition, we extended the application
of these multicolor Nano-lanterns to simultaneous monitoring of multiple gene expression or Ca2+ dynamics in different cellular compartments in a single cell.