Roger Tsien, the exuberant and resourceful UC San Diego researcher who shared the 2008 Nobel Prize in chemistry for helping to find a more effective way to peer inside cells and organisms, died on Aug. 24. He was 64.

Tsien passed away while visiting Eugene, Oregon, said UC San Diego Chancellor Pradeep Khosla, who broke the news to the campus community on Wednesday. The precise cause of death has yet to be determined.

Tsien, a first-generation American who began to explore chemistry at age 8, was hailed for “illuminating” the study of such diseases as cancer and HIV. He teamed with fellow scientists Osamu Shimomura and Martin Chalfie to turn green fluorescent protein (GFP), which is found in jellyfish, into a research tool.

Khosla recalled the collaboration, saying in a statement: “Shimomura identified the crucial jellyfish protein and revealed that it glowed bright green under ultraviolet light. Chalfie showed how it could be used as a biological marker. Combining his deep skills in chemistry and biology, Tsien found ways to make GFP glow more brightly and consistently; then he created a full palette of fluorescent proteins that scientists could use to track different cellular processes at the same time.


“GFPs have become a fundamental fixture in life sciences labs around the world, allowing researchers to look into cells or whole animals, to watch molecules interact in real-time and ask questions once thought impossible.”

Two transgenic mice expressing green fluorescent protein under ultraviolet illumination on either side of a non-transgenic mouse. ( / Ingrid Moen, Charlotte Jevne, Jian Wang, etc. Gene expression in tumor cells and stroma, BMC Cancer. 2012, 12:21.)

After winning the Nobel in 2008, Tsien told The San Diego Union-Tribune, “I’ve always been attracted to colors. Color helps make the work more interesting and endurable. It helps when things aren’t going well. If I had been born color-blind, I probably never would have gone into this.”

The news of Tsien’s death caused mourning across the Torrey Pines Mesa in La Jolla, home to one of the nation’s largest life-science clusters.


“Roger Tsien was truly one of the most remarkable and inspiring scientists of our time,” says Elizabeth Blackburn, a Nobel laureate and president of the Salk Institute for Biological Studies in La Jolla.

“He will be sorely missed as a colleague for his revolutionary work and keen mind, and also as a wonderful person. I felt privileged to get to know him over the years.”

Nobel laureate K. Barry Sharpless of the Scripps Research Institute in La Jolla, said, “Rarely are the smartest people the most creative, too — but Roger was both.”

Kristiina Vuori, president of the Sanford Burnham Prebys Medical Discovery Institute in La Jolla, said, “The mesa is a little darker with the passing of Nobel laureate Roger Tsien. His death is a huge loss to the scientific world. Our thoughts are with his family, friends and colleagues and we will continue to be inspired by the remarkable scientific discoveries he made through the years.”


Bioluminescence researcher Nathan Shaner, who studied in Tsien’s lab, said he was struggling with shock and disbelief.

“He gave me a huge opportunity,” said Shaner, a founding investigator of the nonprofit Scintillon Institute for Biomedical and Bioenergy Research in Sorrento Valley.

“He was the smartest person I’ve ever met, the most creative, and he was also incredibly humble about his place in the big picture,” Shaner said.

Shaner said Tsien gave students great freedom to pursue their projects. He would frequently ask for updates on their progress, but otherwise remain in the background.


“He was very good about letting us figure things out for ourselves,” Shaner said. “I really learned to be independent.”

Shaner and colleagues put green fluorescent protein to artistic use by using genetically engineered bacteria to draw a multicolored San Diego beach scene. Other scientists have adopted this new artistic medium.

The diversity of genetic mutations is illustrated by this San Diego beach scene drawn with living bacteria expressing 8 different colors of fluorescent proteins. They are derived from green fluorescent protein, the use of which was pioneered by Roger Tsien, and from dsRed fluorescent protein. ( / Artwork by Nathan Shaner, photography by Paul Steinbach, created in the lab of Roger Tsien in 2006)

Roger Yonchien Tsien was born in New York City on Feb., 1, 1952. His father, Hsue Chu, was an engineer. His mother, Yi Ying Li, trained as a nurse.


His father found various jobs, but those early years weren’t easy. Roger Tsien wrote in his Nobel biography that the family “chose a new housing development in Livingston, N.J., but the developer refused to sell to us, saying that they could not permit Livingston to become a Chinatown, nor could they afford the likelihood that other customers would refuse to buy houses next to a Chinese family.

“My parents appealed to the Governor of New Jersey, Robert Meyner. His office sent a letter to the developers warning them that racial discrimination was illegal.”

Roger Tsien prospered as a student, and was awarded first prize in the 1968 Westinghouse Science Talent Search for high school seniors.

“I remember being envious of my fellow finalists, who were much more adult and sophisticated,” Tsien wrote in his bio. “Also their projects and exhibits seemed much more exciting and explainable than mine. I felt intimidated by the senior judge, Glenn Seaborg, partly because of his commanding height, partly because he was chairman of the U.S. Atomic Energy Commission, partly because of his 1951 Nobel Prize for work in inorganic chemistry.”


Tsien went on to study chemistry and physics at Harvard College, and later earned a doctorate in physiology at the University of Cambridge in England. He became a junior professor at UC Berkeley before landing at his permanent home, UC San Diego, in 1989.

“UCSD ... was much younger, roomier, faster-growing, and less tradition-bound than Berkeley, which I felt more than compensated for its lesser fame.” Tsien wrote in his bio.

Tsien earned many professional honors, including being elected to the Institute of Medicine and the National Academy of Sciences.

He was also known for and sticking hard and fast to the facts of science. This side of his personality surfaced in front of 400 people in 2013 at the Salk, when Tsien got into an argument with Nobel laureate James Watson during a public lecture.


Tsien didn’t agree with what Watson was saying about oxidants and antioxidants and stood to offer a different perspective. Watson tried to blow him off and dismissively said, “All you have to do is think clearly and these difficulties vanish.”

Tsien calmly replied by telling the agitated Watson that he could find the real facts of the matter by cracking open a particular book. They traded sour looks before a Salk professor stepped in to restore order.

Tsien made light of the situation as he left the auditorium, telling the Union-Tribune: “You should take all elderly scientists with a grain of salt — including me.”

Union-Tribune staff writer Bradley J. Fikes contributed to this story.