Photochromic fluorescent protein “Dronpa”

Inventors

Atsushi Miyawaki, Ryoko Ando and Hideaki Mizuno (Laboratory for Cell Function Dynamics)

Background

Technologies to visualize biological molecules using fluorescent protein labels derived from aequorea victoria, coral or actinia are in widespread use. Current fluorescent imaging techniques have the drawback that they can provide fluorescent signal distributions under steady-state conditions but not dynamics of the molecule in microscopic observation. Biological molecules move continuously and their movements depend on surrounding conditions such as stimulation from the environment. What is needed is a technology that would allow repeated measurement of the dynamics of biological molecules over time using photo-labeling.

Summary

The inventors modified protein discovered from Echinophyllia aspera and developed a photochromic fluorescent protein “Dronpa”. Dronpa fluorescence is switched on and off by two different wavelengths of light. The fluorescence disappears when illuminated with a blue argon laser beam (488 nm), and reappears when illuminated with a violet semiconductor laser beam (405 nm).

Fig.1: Fluorescence of Dronpa can be switched on and off by illumination.

Fig.2: Behavior of MAPK in the presence or absence of EGF.

Fluorescence is cleared by 488 nm laser, and gray portion is activated by 405 nm laser to analyze behavior of MAPK in the presence or absence of EGF.

Fig.3: Dronpa switches letters between visible and invisible.

Merits

• Protein fluorescence can be reversibly switched on and off.
• Enables repeated measurement of in vivo behavior of biological molecules.

Application

• Screening of medicines using behavior of biological molecules as an indicator

References

• 1.US Patent No.7897385, US Patent No.8034614
• 2.Ando R et al., Science 2004 Nov 19; 306 (5700):1370-3