MIDDLEBURY, Vt. – The Johns Hopkins University professor who won the 2009 Nobel Prize in physiology or medicine explained to Middlebury students and community members on March 9 how her “curiosity-driven research” led to discoveries that have advanced medical science.
Carol Greider, the Daniel Nathans professor and director of molecular biology and genetics at the Johns Hopkins Institute for Basic Biomedical Sciences, shared the Nobel Prize with two other researchers for discovering that the ends of chromosomes, or telomeres, are composed of simple, repeating blocks of DNA, and that the blocks are found in all organisms.
Her research, combined with the work of Elizabeth Blackburn at the University of California, San Francisco, and Jack Szostak at Harvard, her co-Nobel Prize recipients, has advanced science’s understanding about certain types of cancer and about age-related degenerative diseases.
Professor Greider’s path to discovery started more than 25 years ago while investigating the genetics of the single-celled, pond-dwelling protozoan called Tetrahymena. Curious about the mechanics that protected the ends of telomeres when cells divided, she studied this particular microorganism because it contained about 40,000 chromosomes, as compared with a human being’s 23 pairs of chromosomes.
“If you really want to understand something fundamental in biology, you go to the source,” she said. “You go to an organism that [demonstrates] that biology the best.”
Working alongside Professor Blackburn, who was then at UC-Berkeley, Greider looked for answers as to how telomeres are replicated every time a cell divides.
“We knew about the problem of telomere shortening that occurred with DNA replication, where you would lose these repeats on the ends of chromosomes. That’s when we discovered this enzyme that we called telomerase – telomerase because it synthesizes telomere repeats – and it’s the telomerase that takes the raw material and adds it on the ends of chromosomes.”
Greider determined that an organism’s telomerase contains an RNA component that serves as a template for its particular telomere DNA repeat sequence. This insight into telomere-end maintenance laid the foundation for studies that are looking at telomeres and telomerase as keys to certain types of cancer and age-related conditions in humans.
It is now well-accepted, Greider explained, that telomeres are required to protect the ends of chromosomes, telomerase is essential for telomere maintenance, telomere shortening leads to cell death or cellular deterioration, short telomeres can limit the growth of cancer cells, and short telomeres can also limit tissue renewal and contribute to age-related degenerative disease.
She concluded her 40-minute presentation saying that fundamental discoveries, such as hers with single-cell creatures, often lead to clinical insights. “New discoveries can come from the most unlikely places,” the Nobel Prize laureate said. “Curiosity-driven research provides unexpected discoveries that have implications for human health."
Greider is the second Nobel Laureate to speak at Middlebury this academic year. In October 2014, the 2008 Nobel Prize winner in chemistry, Martin Chalfie, spoke at Middlebury on the same Dana Auditorium stage as Professor Greider.
Greider’s talk at Middlebury was made possible by the George B. Saul II Lecture Fund in conjunction with the Department of Biology, Office of the President, Albert D. Mead Professorship, Program in Molecular Biology and Biochemistry, Education Studies, Middlebury STEM Innovation Project, and Women in STEM at Middlebury.
– With reporting by Robert Keren