The Japanese freshwater eel (Anguilla japonica) has more to offer biologists than a tasty sushi snack. Its muscle fibers produce the first fluorescent protein identified in a vertebrate, researchers report in Cell.
Fluorescent proteins are as standard a tool for cell biologists as wrenches are for mechanics. They do not produce light themselves, but glow when illuminated. The 2008 Nobel Prize in Chemistry was awarded for the discovery and development of such molecules, which are used to tag proteins or to track how genes are expressed. The molecules have been engineered to produce light in a variety of hues and brightnesses, but those discovered until now in nature all came from non-vertebrates, mainly microbes, jellyfish, and corals