I was amused by the name for the “First fluorescent protein identified in a vertebrate”. The researchers named it UnaG, after the Japanese freshwater eel “unagi” from which it was identified. The brief announcement in Nature News and Comment, First fluorescent protein identified in a vertebrate, claims that
“It’s totally different” from other fluorescent proteins. “There’s not anything you can point to that’s the same.” For example, instead of producing light with a ‘chromophore’ that is part of the protein sequence, as the classical Green Fluorescent Protein (GFP) does, UnaG fluoresces when it binds a naturally occurring small molecule called bilirubin, a breakdown product of haemoglobin.
The article has a cool picture of an eel glowing green when illuminated with a blue light. They say that American and European eels also have UnaG in their muscles. I wonder why no one has noticed this fluorescence before.