First Vertebrate Fluorescent Proteins Found in Japanese Eels: Medical Science Could Benefit From the Discovery

Scientists have found the first glowing, fluorescent protein in a vertebrate animal. The protein was found in the Japanese freshwater eel, and besides being an interesting thing to think about next time you're eating sushi, researchers say it could hold a key to simpler, better tests for human liver function.

Researchers reported their findings in Cell on Thursday, identifying the first fluorescent protein known to vertebrates, as well as the gene that codes for it. Until now, the only fluorescent proteins found by scientists came from invertebrates like jellyfish and other life like microbes. Researchers Dr. Atsushi Miyawaki and Dr. Akiko Kumagai named the newly discovered protein UnaG, in homage to the Japanese unagi, which is the Japanese word for the freshwater eel, which you might find in any sushi dish.

"I don't think anyone would have thought that eels would have such a bright fluorescent protein," said Robert Campbell, an expert in protein engineering at the University of Alberta in Edmonton, Canada to Scientific American. UnaG is a completely new find, he says. "It's totally different" from other known fluorescent proteins. "There's not anything you can point to that's the same."

Another difference in the UnaG protein, compared to other known fluorescent proteins, is that, unlike the others, it stays fluorescent even in low-oxygen environments in cells. This means that UnaG may be able to make some routine hospital tests for humans more efficient. Hospitals use fluorescent proteins to test for liver diseases and visualize liver function and cancerous tumors, but some areas inside tumors are anaerobic - meaning levels of oxygen are low inside the cells. UnaG holds a possibility of helping medical professionals visualize those areas in a better way.

The protein researchers got their first clue from research in 2009, when food chemists found that eel muscle tissues glow green when illuminated by blue light. Miyawaki and Kumagai isolated the genetic codes that make the protein and gave it the name UnaG. Now the protein could be the start of a world of possibilities in human health testing and physiological research, says Miyawaki: "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."