Center for Relativistic Laser Science

2017 120th KCS Meeting

UnaG is a fluorescent protein discovered form Japanese Eel, whose fluorescence arise only when the protein binds to bilirubin (BR), a nonfluorescent metabolite. We investigated UnaG’s photoswitchable nature caused by repetitive binding and unbinding of BR. Mainly the photooxidation of BR induces the off-switching of UnaG fluorescence. When the damaged BR is exchanged to fresh one,  the protein recovers the fluorescence capability. Since more than 50% of UnaG molecules can survive after >300 switching cycles, UnaG should be an attractive candidate for a fluorescent probe for single-molecule localization based super-resolution imaging, especially for the long-term live-cell imaging. We imaged various UnaG labeled subcellular structures with sub-diffraction limit resolution in live Cos7 cells. As a result, we can increase the number of super-resolution snapshots more than 10 times with UnaG than conventional fluorescent probes (except lipophilic dyes that have limited applications).

References

[1] A. Kumagai, R. Ando, H. Miyatake, P. Greimel, T. Kobayashi, Y. Hirabayashi, T. Shimogori and A. Miyawaki, Cell, 153, 1602 (2013).