FOR IMMEDIATE RELEASE

July 8, 2022

A Highly Photostable Fluorescent Protein- Technology That Allows For Quantitative Observation of CellularMicrostructures and Viruses RIKEN
Tohoku UniversityKitasato University
Kao Corporation
A joint research group consisting of researchers from the Laboratory for Cell Function Dynamics ofthe RIKEN Center for Brain Science and the Biotechnological Optics Research Team of the RIKEN
Center for Advanced Photonics; the Asamushi Research Center for Marine Biology, Graduate Schoolof Life Sciences, Tohoku University; the Ōmura Satoshi Memorial Institute, Kitasato University; andthe Safety Science Research Laboratories, Kao Corporation, promotes sustainable bioimaging byutilizing a jellyfish-derived green fluorescent protein StayGold, which is bright and exhibits minimal
fading. StayGold improves spatiotemporal resolution and dramatically extends the observation period.
This finding offers a new and powerful tool for the bioimaging community, in which most experimenters
encounter the challenging issue of photobleaching[1] of fluorescent proteins.
On the basis of gene expression[2] analysis of the jellyfish Cytaeis uchidae[3] done by researchers fromTohoku University, researchers from RIKEN created StayGold, a bright fluorescent protein variant withthe unique property of minimal photobleaching, through their molecular cloning and mutagenesis
studies on a wild-type fluorescent protein. Fluorescent labelling of organelles such as the endoplasmic
reticulum, mitochondria, and microtubules with StayGold has revealed dynamic structural changes that
could not be observed previously due to the photobleaching of conventional fluorescent proteins. Inaddition, StayGold was molecularly linked to the anti-Spike VHH antibody[4] developed by researchers
from Kitasato University and Kao Corporation to visualize the process of virion maturation in SARSCoV-2-infected cells, which is appealing to scientists in medicine who are working furiously to develop
ways to reliably detect SARS-CoV-2 and other infectious viruses.
These findings were reported in Nature Biotechnology Online (published on April 25).

Green fluorescence emitted from the jellyfish Cytaeis uchidae(Top view of jellyfish umbrella imaged under blue light. The diameter of the umbrella is 1.3 mm.)
■ Publication information
Title:A highly photostable and bright green fluorescent protein
Authors:
Masahiko Hirano1, Ryoko Ando2, Satoshi Shimozono 2, Mayu Sugiyama2, Noriyo Takeda3,10,Hiroshi Kurokawa2, Ryusaku Deguchi4, Kazuki Endo4,11, Kei Haga5, Reiko Takai-Todaka5, Shunsuke
Inaura6, Yuta Matsumura6, Hiroshi Hama2, Yasushi Okada 7,8, Takahiro Fujiwara9, Takuya Morimoto6,
Kazuhiko Katayama 5, and Atsushi Miyawaki 1,2
1

Biotechnological Optics Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan. 2Laboratory
for Cell Function Dynamics, RIKEN Center for Brain Science, Saitama, Japan. 3Asamushi Research Center forMarine Biology, Tohoku University, Aomori, Japan. 4Department of Biology, Miyagi University of Education,Sendai, Japan. 5Department of Infection Control and Immunology, Ōmura Satoshi Memorial Institute, Kitasato
University, Tokyo, Japan. 6Safety Science Laboratories, Kao Corporation, Tokyo, Japan. 7Laboratory for Cell
Polarity Regulation, RIKEN Center for Biosystems Dynamics Research, Osaka, Japan. 8Department of Cell
Biology and Department of Physics, UBI and WPI-IRCN, The University of Tokyo, Tokyo, Japan. 9Institute forIntegrated Cell-Material Sciences, Kyoto University, Kyoto, Japan. 10Current address: Graduate School ofIntegrated Sciences for Life, Hiroshima University, Hiroshima, Japan. 11Current address: Narita Elementary
School, Miyagi, Japan.

Journal:Nature Biotechnology
DOI:
10.1038/s41587-022-01278-2■ Footnote[1] Photobleaching
A chromophore is a structural unit that absorbs the visible range of light and determines the color ofobjects. Fluorescent proteins form their chromophores internally. Degradation of chromophores causes
photobleaching, leading to irreversible loss of color. This loss of color inevitably results in loss offluorescence.

[2] Gene expression analysis
In the context of this article, this refers to data obtained from comprehensive analyses (transcriptomeanalyses) of messenger RNA (mRNA) of particular tissues.
[3] Cytaeis uchidae
The Cytaeis uchidae is a jellyfish belonging to the Cnidaria division, Hydrozoa class, andAnthomedusae order. Individual Cytaeis uchidae have a spherical body 1–2 mm in diameter. Cytaeis
uchidae can be raised in laboratories and has drawn attention as an experimental material for
reproductive biology and a school science material.
[4] VHH antibody
Camelids such as alpacas produce antibodies formed only of heavy chains with no light chains. Thevariable domain of this heavy chain antibody is referred to as VHH (variable domain of heavy chain ofheavy chain) and is used as the smallest protein segment that recognizes antigens. Haga et al. (KitasatoUniversity) have demonstrated that symptoms of SARS-CoV-2 infected hamsters could be alleviatedusing the anti-SARS-CoV-2 spike VHH antibody.