An optical marker based on the UV-induced green-to-red photoconversion of a fluorescent protein

• DOI: 10.1073/pnas.202320599
• Publication Date: 2002-10-01T16:58:28Z
• Authors: Ryoko Ando; Hiroshi Hama; Miki Yamamoto-Hino; Hideaki Mizuno; Atsushi Miyawaki
• Keywords: Chromophore; Green-light; Far-red

We have cloned a gene encoding fluorescent protein from stony coral, Trachyphyllia geoffroyi , which emits green, yellow, and red light. The protein, named Kaede, includes tripeptide, His-Tyr-Gly, that acts as green chromophore can be converted to red. fluorescence is comparable in intensity the stable under usual aerobic conditions. found green-red conversion highly sensitive irradiation with UV or violet light (350–400 nm), excites protonated form of chromophore. excitation lights used elicit do not induce photoconversion. Under conventional epifluorescence microscope, Kaede expressed HeLa cells turned graded fashion response illumination; maximal illumination resulted 2,000-fold increase ratio red-to-green signal. These color-changing properties provide simple powerful technique for regional optical marking. A focused pulse creates an instantaneous plane source within cytosol. spot spreads rapidly throughout cytosol, indicating its free diffusibility compartment. extensive diffusion allows us delineate single neuron dense culture, where processes originating many different somata are present. Illumination onto soma Kaede-expressing filling all fluorescence, allowing visualization contact sites between neurons interest.