A freshwater eel popular among sushi aficionados holds the first fluorescent protein found to have naturally occurred in a vertebrate.
A fluorescent protein – the first ever found naturally occurring in a vertebrate – has been spotted in a freshwater eel that is common on sushi menus but becoming scarce in the wild.
Anguilla japonica, also known as unagi, is born in the sea. As eggs and larvae they are carried by ocean currents to rivers, lakes, and estuaries in Japan, China, Taiwan, Korea, and Vietnam, where they spend their lives until returning to the sea to spawn.
The carnivorous fish also possess a glow-in-the-dark protein in their muscles, as scientists at Japan's RIKEN Brain Science Institute have found. In a study published in the scientific journal Cell, researchers describe what they've named UnaG, the first fluorescent protein found to have come from a vertebrate. The researchers believe that the glowing protein aids in the species' migration.
UnaG is a fatty-acid-binding protein found in the unagi's muscle fibers. The researchers were surprised to find that it glowed only when activated by a chemical called bilirubin, a breakdown product of molecules found in blood. The scientists also identified the protein in the American and European species of Anguilla.