Carolyn Widney Greider was born on April 15, 1961. She is an American scientist who studies molecules, cells, and how living things grow. She is a Distinguished Professor of Molecular, Cell, and Developmental Biology at the University of California, Santa Cruz.

In 1984, while working as a graduate student under Elizabeth Blackburn at the University of California, Berkeley, Greider discovered an enzyme called telomerase. She studied the structure of telomeres, which are the ends of chromosomes. In 2009, Greider, Blackburn, and Jack W. Szostak received the Nobel Prize for Physiology or Medicine. They were honored for discovering that telomeres are protected from shortening by the enzyme telomerase.

Early life and education

Greider was born in San Diego, California. Both of her parents worked in schools or universities. Her father, Kenneth Greider, was a physics professor. Her family moved to Davis, California, where she lived for many years and graduated from Davis Senior High School in 1979. She earned a B.A. in biology from the College of Creative Studies at the University of California, Santa Barbara, in 1983. During this time, she also studied at the University of Göttingen and made important discoveries there.

Greider has dyslexia, which means she finds reading and writing challenging. She says her ability to develop other skills helped her succeed as a scientist because she often needs to think about many things at once and use that thinking to solve problems. She first noticed signs of dyslexia in first grade when she saw patterns in mistakes, such as writing words backward, on her graded work. She began memorizing words instead of trying to sound them out. She worked hard to overcome her dyslexia and became successful in her career. She believes her dyslexia helped her notice differences and make unusual choices, such as studying Tetrahymena, a unique organism.

Greider had trouble getting into graduate school because her low GRE scores were affected by her dyslexia. She applied to thirteen graduate programs and was accepted to only two: the California Institute of Technology and the University of California, Berkeley. She chose to study at Berkeley.

Discovery of telomerase

Greider earned her Ph.D. in molecular biology in 1987 at the University of California, Berkeley, under the guidance of Elizabeth Blackburn. During her time at Berkeley, Greider and Blackburn discovered how telomeres, which are protective structures at the ends of chromosomes, are maintained by an enzyme called telomerase. Greider joined Blackburn's laboratory in April 1984 to search for an enzyme believed to add extra DNA bases to the ends of chromosomes. Without these bases, which repeat a six-base pair pattern, chromosomes become shorter during DNA replication. This shortening can eventually lead to chromosome damage, cell aging, or the fusion of chromosomes, which may cause cancer. Blackburn and Greider studied the enzyme in Tetrahymena thermophila, a freshwater protozoan with many telomeres.

On December 25, 1984, Greider found results suggesting that a specific enzyme was likely responsible for adding DNA bases. After six months of further research, Greider and Blackburn confirmed that the enzyme was responsible for telomere addition. They shared their findings in the journal Cell in December 1985. The enzyme, first named "telomere terminal transferase," is now known as telomerase. Telomerase helps rebuild the ends of chromosomes and influences how long cells can live.

Greider continued her research to confirm her discovery by investigating how telomerase works. She used enzymes that break down RNA and observed that telomeres stopped growing, showing that RNA plays a role in the enzyme's function.

Subsequent career

Carol Greider began her laboratory work as a Cold Spring Harbor Laboratory Fellow and held a faculty position at the Cold Spring Harbor Laboratory on Long Island, New York. She continued her research on Tetrahymena telomerase, cloning the gene that produces the RNA component and showing that this RNA provides the template for the TTGGGG telomere repeats in 1989. She also proved that telomerase is processive in 1991. In 1994, she recreated Tetrahymena telomerase in a laboratory setting and identified how the enzyme uses its RNA template in 1995. Greider worked with Calvin Harley to demonstrate that telomere shortening causes cells to stop dividing, a process known as cellular senescence, in 1990. To test this further, researchers studied mouse and human telomerase in 1993 and 1995, and the mouse telomerase RNA component was cloned in 1995.

In the mid-1990s, Greider collaborated with Ronald A. DePinho to create the first telomerase knockout mouse. This research showed that while telomerase is not essential for survival, shortened telomeres lead to harmful effects, often called premature aging. Greider joined the Scientific Advisory Board of Geron, a biotechnology company founded by Michael D. West (now CEO of AgeX Therapeutics), in the mid-1990s and remained on the board until 1997.

In 1997, Greider accepted a faculty position at the Johns Hopkins University School of Medicine. She continued studying telomerase-deficient mice and observed that the sixth generation of these mice became completely sterile. However, when these mice were bred with normal mice, they could restore their telomeres. Greider further studied the structure of vertebrate telomerase RNA, identifying its secondary structure in 2000 and its template boundary in 2003. She also analyzed the pseudoknot structure in human telomerase RNA in 2005. In addition to research on Tetrahymena and mammals, Greider studied telomeres and telomerase in the yeast Saccharomyces cerevisiae, clarifying how yeast cells without telomerase use recombination to maintain telomeres in 1999 and 2001. She also showed that short telomeres trigger a DNA damage response in yeast in 2003.

Greider, Elizabeth Blackburn, and Jack Szostak shared the 2006 Albert Lasker Award for Basic Medical Research for their work on telomeres. They later received the Nobel Prize in 2009. In February 2014, Greider was named a Bloomberg Distinguished Professor at Johns Hopkins University. She served as director and professor in the Department of Molecular Biology and Genetics at Johns Hopkins Medicine and was promoted to Daniel Nathans Professor in 2004. As of 2021, she is a Distinguished Professor of Molecular, Cellular, and Developmental Biology at UC Santa Cruz.

Greider’s laboratory trains students and post-doctoral researchers to study the relationship between telomere biology and disease. The lab uses tools such as yeast, mice, and biochemical methods to examine how telomeres shorten over time. Researchers also investigate how short telomeres might help control tumor regrowth. Future work will focus on understanding how telomeres are processed, regulated, and lengthened.

Personal life

In 1992, Greider married Nathaniel C. Comfort, who was also a teacher or researcher. They divorced in 2011, and she has two children.

Awards and honors

• Pew Scholar in the Biomedical Sciences (1990–1994)
• Gairdner Foundation International Award (1998)
• Rosenstiel Award in Basic Medical Research (1998) (shared with Elizabeth Blackburn)
• Member of the American Society for Cell Biology (1999)
• Passano Foundation Award (1999) (shared with Elizabeth Blackburn)
• Harvey Society Lecture (2000)
• Academy of Achievement Golden Plate Award (2000)
• Fellow of the American Academy of Arts and Sciences (2003)
• Member of the National Academy of Sciences (2003)
• Richard Lounsbery Award (2003), National Academy of Sciences
• Member of the American Society for Biochemistry and Molecular Biology (2004)
• Lila Gruber Cancer Research Award (2006)
• Albert Lasker Award for Basic Medical Research (2006) (shared with Elizabeth Blackburn and Jack Szostak)
• Wiley Prize in Biomedical Sciences (2006) (shared with Elizabeth Blackburn)
• Dickson Prize in Medicine (2007)
• Louisa Gross Horwitz Prize of Columbia University (2007) (shared with Elizabeth Blackburn and Joseph G. Gall)
• The Pearl Meister Greengard Prize (2008) (shared with Elizabeth Blackburn and Vicki Lundblad)
• Nobel Prize in Physiology or Medicine (2009) (shared with Elizabeth Blackburn and Jack Szostak)
• Paul Ehrlich and Ludwig Darmstaedter Prize (2009) (shared with Elizabeth Blackburn)
• Member of the Institute of Medicine (2010)
• Member, American Philosophical Society (2016)
• Pinnacle Award (2019), Association for Women in Science
• Award for Excellence in Molecular Diagnostics, Association for Molecular Pathology (2022)

Selected works

• Greider, C. W. & Blackburn, E. H. (1985). "Discovery of an enzyme that adds DNA to telomeres in Tetrahymena extracts." Cell. 43 (2 Pt. 1): 405–413. doi: 10.1016/0092-8674(85)90170-9. PMID 3907856.
• Greider, C. W. & Blackburn, E. H. (1996). "Telomeres, Telomerase, and Cancer." Scientific American. 274 (2): 92–97. Bibcode: 1996SciAm.274b..92G. doi: 10.1038/scientificamerican0296-92. PMID 8560215.