Tsien, << chee YEHN, >> Roger Yonchien (1952-2016), an American chemist, won a share of the 2008 Nobel Prize in chemistry. Tsien won for his work on the green fluorescent protein (GFP). GFP is a naturally glowing molecule that glows green when exposed to blue or ultraviolet light. It can be linked to other proteins, “tagging” them so they can be viewed with a microscope. The award was shared with two other GFP researchers, the American biologist Martin Chalfie and the Japanese-born American chemist Osamu Shimomura.
Shimomura announced the discovery of GFP in 1962. He isolated it from the glowing cells of the jellyfish Aequorea victoria. He then found GFP to be unique in several ways. Most importantly, he found that once GFP was made in the jellyfish, it did not need added energy to glow. Many other molecules that glow need a steady supply of energy to do so. In addition, it was a relatively small molecule. In 1988, Chalfie recognized that these qualities make GFP an ideal protein “tag.” In the 1990’s, Chalfie, Tsien, and other scientists developed a technique showing how GFP could be used as a tag. Because GFP is small, it did not interfere with the normal function of the tagged protein.
GFP glows one color—green. Tsien modified the protein to glow brighter and produce other colors. He was able to produce blue, yellow, and cyan (blue-green) versions of the protein. However, he was not able to make it glow red. Instead, Tsien turned to a GFP-like protein found in coral called DsRed. That protein glowed red, but it was too large to make an effective tag. Tsien modified DsRed, reducing it to a size similar to that of GFP. He also modified it to produce several additional colors.
The tagging technique first proposed by Chalfie enables scientists to study the movement and function of proteins, including those involved in such diseases as cancer and Alzheimer’s disease. By increasing the number of colors available, Tsien enabled them to tag and study many different proteins at the same time.
Tsien was born in New York City on Feb. 1, 1952. He received his doctor’s degree in physiology from the University of Cambridge in England in 1977. Afterwards, he remained at Cambridge as a researcher. He became a professor at the University of California at Berkeley in 1981. In 1989, he became a professor at the University of California at San Diego and a researcher at the Howard Hughes Medical Institute Research Lab. He cofounded two companies: Aurora Biosciences Corporation in 1994 and Senomyx Incorporated in 1998. Tsien died on Aug. 24, 2016.
See also Chalfie, Martin ; Shimomura, Osamu .
