Three scientists—Osamu Shimomura, Martin Chalfie, and Roger Tsien—will share this year's Nobel Prize in Chemistry for their work on green fluorescent protein (GFP), the Nobel Foundation announced today.

Thanks to Shimomura's 1962 discovery of GFP from the Aequorea victoria jellyfish, Chalfie's demonstration of GFP's use as a tag for DNA, and Tsien's expansion of the technology, researchers today are able "to watch processes that were previously invisible, such as the development of nerve cells in the brain or how cancer cells spread," according to the Nobel Foundation. The three scientists will share the $1.4 million (10 million Swedish Kronor) prize.

"I am very pleased and honored," Tsien told a news conference over the phone from California, according to Reuters today. "I didn't expect it. There had been some rumors but from sources who were very questionable," he joked.

"This was a neat trio in that it brings together the excitement of discovery as well as someone who heard about it [Chalfie] and thought, 'Wow, how could I use this in my work?'," says Catherine Hunt, corporate sustainability director for Rohm and Haas Company in Philadelphia and immediate past president of the American Chemical Society. "That's what scientists do; they make connections."

Shimomura, currently a researcher at the Marine Biological Laboratory, Woods Hole, Mass., in 1962 first isolated GFP from the Aequorea victoria jellyfish, which drifts with the currents off the west coast of North America. A Japanese citizen born in 1928, Shimomura initiated decades of discovery when he identified GFP's ability to glow bright green under ultraviolet light.

Columbia University professor and researcher Chalfie, a Chicago native born in 1947, demonstrated the value of GFP as a luminous genetic tag for various biological phenomena. In one of his first experiments, he colored six individual cells in the transparent roundworm Caenorhabditis elegans -- an organism commonly used in research—with the aid of GFP.

Tsien, a University of California, San Diego, La Jolla, Calif., researcher born in New York in 1952, contributed to the general understanding of how GFP glows and extended the color palette beyond green. That allowed researchers to give various proteins and cells different colors and follow several different biological processes at the same time. In 1980 Tsien began to synthesize dyes that track calcium concentration in cells, making it possible to study currents in single brain cells and networks of such cells.

"This is an example of chemistry enabling so many other fields," John Frangioni, an associate professor of both medicine and radiology at Harvard's Beth Israel Deaconess Medical Center in Boston, told "It highlights how chemistry can touch biology, medicine and other very practical endeavors. I'm gratified that the choice was one of a technology that enabled so may other areas of science."

Using this glowing marker researchers can watch the movements, positions and interactions of tagged proteins and spot signs of trouble, such as when a protein malfunctions, that can lead to illness and disease, including nerve cell damage during Alzheimer's disease or how insulin-producing beta cells are created in the pancreas of a growing embryo.

The green fluorescent protein allows researchers to trace and monitor cells in a very conclusive way, Hunt said. "If you want to look for something like HIV, you can see it in real time. If you want to look for arsenic in drinking water, they've developed a GFP to find that under UV light." GFP could also be used for finding biological agents that might be used in a terrorist attack.

Tsien's greatest contribution is where he took the technology, making numerous modifications, Hunt said. "Roger moved the field to a whole new level by figuring out how the chemicals can be manipulated," Frangioni added. "What was a single discovery of a single protein in a single jellyfish has turned into dozens of fluorescent proteins."

The discovery and development of GFP has also allowed scientists to study animal cells without having to take them out of the body, "putting us on the brink of being able to treat diseases that decades ago we thought it wouldn't be possible to treat," Frangioni said. "We use the technology to study cancer and how it metastasizes, how genes are turned on and off and how proteins in a cell behave after stimulation."

The choice was surprising only because the technology is relatively new, Frangioni said. Hunt agreed: "This work began 30 years ago, while some people might say that's a long time, in truth it's really fast."