Carol W. Greider

Lore & Background

Greider was born in San Diego, California, to academic parents; her father was a physics professor. She graduated from Davis Senior High School in 1979 and earned a B.A. in biology from the College of Creative Studies at the University of California, Santa Barbara in 1983. Greider is dyslexic and has stated that her compensatory skills contributed to her success as a scientist. She initially had difficulty getting into graduate school due to low GRE scores from her dyslexia, but was accepted to the California Institute of Technology and the University of California, Berkeley, choosing the latter.

Greider joined Elizabeth Blackburn's laboratory in April 1984 to search for the enzyme hypothesized to add extra DNA bases to chromosome ends.

Reader's Guide

Greider's discovery of telomerase in 1984 fundamentally changed understanding of chromosome biology and cellular aging. By identifying the enzyme that rebuilds telomere tips, she provided a mechanism for how cells maintain chromosome integrity during replication, countering the progressive shortening that would otherwise lead to deterioration, senescence, or cancer-causing fusion. Her work, alongside Elizabeth Blackburn and Jack Szostak, established that telomeres are protected by telomerase, a finding recognized with the 2009 Nobel Prize. Greider's subsequent research elucidated telomerase's RNA template, processivity, and role in cellular senescence, and she produced the first telomerase knockout mouse, demonstrating that short telomeres cause deleterious phenotypes resembling premature aging. Her career, marked by overcoming dyslexia and pursuing research on an unusual organism (Tetrahymena), exemplifies how persistence and unconventional approaches can yield transformative biological insights. Her ongoing work continues to explore telomere biology and its connections to disease, including tumor reformation.

Did You Know?

• Greider discovered telomerase on December 25, 1984, while a graduate student.
• She is dyslexic and credits her dyslexia with helping her appreciate differences and make unusual decisions, such as working with Tetrahymena.
• Greider applied to thirteen graduate schools and was accepted to only two: California Institute of Technology and the University of California, Berkeley.
• She shared the 2006 Albert Lasker Award for Basic Medical Research with Elizabeth Blackburn and Jack Szostak before receiving the Nobel Prize in 2009.

Early Life and the Dyslexia Advantage

Born in San Diego in 1961 to academic parents—her father was a physics professor—Carolyn Widney Greider grew up in an intellectually rich household. The family relocated to Davis, California, where she completed high school in 1979 before earning a biology degree from UC Santa Barbara's College of Creative Studies in 1983. She also spent time studying at the University of Göttingen, where she made notable discoveries. Greider is dyslexic, a condition she first suspected in first grade when she noticed patterns of reversed letters in her graded work. Rather than sounding out words, she developed a habit of memorizing their spellings. She credits this condition with sharpening her ability to juggle multiple variables simultaneously and to make unconventional choices, such as selecting the unusual protozoan Tetrahymena as a research model. Her dyslexia also made the graduate school application process difficult; low GRE scores led her to apply to thirteen programs, receiving acceptance from only Caltech and Berkeley. She chose Berkeley, setting the stage for the work that would redefine her field.

The Christmas Eve Breakthrough

In April 1984, Greider entered Elizabeth Blackburn's laboratory at UC Berkeley with a clear mission: find the enzyme that was theorized to append extra DNA bases to chromosome tips. Without these additions—repeats of a six-base-pair sequence—chromosomes progressively shorten with each round of replication, ultimately leading to cellular deterioration, senescence, or dangerous chromosome fusions linked to cancer. The pair turned to Tetrahymena thermophila, a freshwater protozoan whose genome carries an unusually large number of telomeres, making it an ideal testbed. On December 25, 1984, Greider's data pointed strongly toward a specific enzyme. After six more months of confirmatory work, including experiments with RNA-degrading enzymes that halted telomere extension—revealing RNA's essential role—they published in the journal Cell in December 1985. The enzyme, initially dubbed "telomere terminal transferase," is now universally called telomerase. It rebuilds chromosome tips and governs cellular lifespan. Greider completed her Ph.D. in molecular biology in 1987.

Expanding the Telomerase Frontier

After Berkeley, Greider established her own laboratory as a fellow and faculty member at Cold Spring Harbor Laboratory on Long Island. There she cloned the gene encoding the RNA component of Tetrahymena telomerase (1989), demonstrated that this RNA serves as the template for the TTGGGG repeat sequence, and showed the enzyme is processive (1991). By 1994 she had reconstituted the enzyme in vitro, and by 1995 she had mapped its template-utilization mechanisms. Collaborating with Calvin Harley, she provided evidence that telomere shortening drives cellular senescence (1990). She then characterized mouse and human telomerase (1993, 1995) and cloned the mouse telomerase RNA component. In a landmark collaboration with Ronald A. DePinho, she produced the first telomerase-knockout mouse, revealing that while the enzyme is not strictly required for survival, progressively short telomeres trigger deleterious phenotypes resembling premature aging. In the mid-1990s she joined the Scientific Advisory Board of Geron, the biotech firm founded by Michael D. West. In 1997 she moved to Johns Hopkins, where she continued exploring telomerase-deficient mice, vertebrate RNA structure, and yeast telomere maintenance.

Recognition and Lasting Impact

The full weight of Greider's contribution was acknowledged in 2006 when she, Blackburn, and Jack W. Szostak shared the Albert Lasker Award for Basic Medical Research. Three years later, in 2009, the trio received the Nobel Prize in Physiology or Medicine for their collective demonstration that telomeres are shielded from progressive shortening by the enzyme telomerase. At Johns Hopkins, Greider served as director and professor of the Department of Molecular Biology and Genetics, and in February 2014 she was elevated to the rank of Bloomberg Distinguished Professor. Her research at Hopkins spanned defining the secondary structure and template boundary of vertebrate telomerase RNA, analyzing pseudoknot architecture in the human enzyme, and investigating how yeast cells null for telomerase maintain their chromosome ends through recombination-based gene conversion. She also showed that short telomeres activate a DNA damage response in yeast. Today she holds the title of Distinguished Professor of Molecular, Cell, and Developmental Biology at the University of California, Santa Cruz, continuing to shape the field she helped create.