Fluorescent proteins were found for the first time in a vertebrate, the Japanese freshwater eel.
The protein could help revolutionize a new test for bilirubin, a critical indicator of liver function, according to a RIKEN Brain Science Institute press release. The findings may also contribute to the endangered eel's conservation.
The eel is considered to be a delicacy in Japan, this coupled with global warming has caused the species' population to decline and researchers know very little about the creature.
Dr. Atsushi Miyawaki and his team were able to clone the bright-green fluorescent protein they named UnaG. The protein allows the eel to glow in the dark.
Similar proteins have been found before in simple species such as jellyfish, but this is the first time they have been discovered in a vertebrate.
The protein is special because it needs the naturally occurring chemical bilirubin in order to glow. Bilirubin is a "slippery molecule universally used in clinical labs around the world as a human blood marker for liver function."
Bilirubin is made when blood hemoglobin breaks down, it can be toxic if there is too much of the substance present in the human body. The molecule can cause the characteristic yellowing of the eyes associated with jaundice and other conditions. Doctor's also look for bilirubin when testing for hemolysis, the loss of red blood cells in anemia.
The researchers found a way to bind bilirubin to UnaG and activate it's glowing response to test for these conditions. This new system could help children in developing countries, where juvenile liver health is a major concern.
"We believe that UnaG provides an unexpected foothold into several important but currently obscure areas of human health including bilirubin metabolism and muscle physiology during endurance exercise," Miyawaki said. "Before the discovery of UnaG, I couldn't imagine that basic science could have such a direct impact on human health. From a simple eel, we found a new path to the clinic."
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