ABSTRACT
Numerous proteins exhibit fluorescence, but the term fluorescent proteins (FPs) generally defines a diverse group of proteins found in marine organisms that are homologues of the prototypical jellyfish. Major achievements were made by R. Y. Tsien and his colleagues, who contributed much to our understanding of how green fluorescent protein (GFP) works and engineered new mutants. The use of blue and cyan FPs for cellular imaging has been more limited than for greens because many require near-UV light for excitation which is phototoxic to mammalian cells. Cyan FPs developed from avGFP bearing a tryptophan substitution in the chromophore have been among the most frustrating to end users due to their low brightness. Red and particularly far-red emitting FPs are useful for imaging deep into tissues. All wild-type RFPs originate from anthozoans and are tetrameric, so a key goal of research was to develop monomeric forms. Researchers in Atsushi Miyawaki’s lab in Japan isolated a green fluorescent protein from the coral Trachyphllia geoffroyi.
