Molecular biologist receives 2009 Nobel Prize in Physiology or Medicine

Molecular biologist Elizabeth H. Blackburn, PhD, 60, of the University of California, San Francisco, today was named to receive the 2009 Nobel Prize in Physiology or Medicine.

Blackburn shares the award with Carol W. Greider of Johns Hopkins University School of Medicine and Jack W. Szostak of Harvard Medical School.

The scientists discovered an enzyme that plays a key role in normal cell function, as well as in cell aging and most cancers. The enzyme is called telomerase and it produces tiny units of DNA that seal off the ends of chromosomes, which contain the body's genes. These DNA units - named telomeres -- protect the integrity of the genes and maintain chromosomal stability and accurate cell division. They also determine the number of times a cell divides -- and thus determine the lifespan of cells.

Telomerase is pronounced (tel-AH-mer-AZE). Telomere is pronounced (TEEL-oh-mere).

The scientists' research sparked a whole field of inquiry into the possibility that telomerase could be reactivated to treat such age-related diseases as blindness, cardiovascular disease and neurodegenerative diseases, and deactivated to treat cancer, in which it generally is overactive.

In recent years, Blackburn and colleagues have investigated the possibility that life stress, the perception of life stress and lifestyle behaviors could take a toll on telomerase and telomeres. They have reported several studies with human participants that suggest a correlation. The findings may offer insight, at the cellular level, into the impact of stress on early onset of age-related diseases.

The scientists were named to receive the prize "for the discovery of how chromosomes are protected by telomeres and the telomerase enzyme," according to the Nobel committee in Stockholm, Sweden.

"Dr. Blackburn's research over the course of more than three decades has revolutionized scientists' understanding of the way in which cells function," said UCSF Chancellor Susan Desmond-Hellmann, MD, MPH. "Her co-discovery of the telomerase has revealed a mechanism that plays a key role in determining the lifespan of cells, as well as the processes of cell aging and cancers.

"Her generous spirit, curiosity and highly collaborative nature have led her to forge research partnerships that have significantly broadened scientists' capacity to understand the remarkable telomerase enzyme. As a scientist, a colleague, a mentor and a woman in science, she is an inspiration to the nation and the world."

UC President Mark Yudof remarked,"The entire University of California community could not be more proud of Dr. Elizabeth Blackburn. Her path breaking work is yet another reminder of the life-changing contributions UC makes to California and to the world."

The roots of telomere and telomerase research trace back to the 1930s, when geneticists hypothesized that protective caps on chromosomes ensure their ability to propagate during cell division, and prevent them from inappropriately melding with one another.

But it was decades later, between 1975 and 1977, that Blackburn, working as a postdoctoral fellow at Yale University with Joseph Gall, discovered the unusual nature of telomeres, with their simple, repeated DNA sequences composing the chromosomes' ends. Their work was published in 1978.

With Szostak, Blackburn established that the DNA repeats stabilize chromosomes. The two also predicted the existence of an enzyme that would add the sequences to the ends of chromosomes, which reside in cells.

In 1985, while a professor at University of California, Berkeley, Blackburn and her then-graduate student Greider reported the discovery of telomerase. Their research showed that, in some organisms, such as the single-celled pond dweller Tetrahymena, telomerase continuously replenishes the chromosome's telomeric tips. In humans, however, researchers including Blackburn and her group showed that telomerase is damped down at certain times in the lives of many types of cells, limiting their ability to self-replenish.

With this discovery, scientists saw the possibility of exploring whether, in humans, the enzyme could be reactivated to prolong cell life to treat age-related diseases, and deactivated to interrupt cancers.