NIH SciEd Blog

Three Americans – Including Two Women -- Share the Nobel Prize in Physiology or Medicine

By: Cindy, Gina, Gloria | November 2 2009 | Category: Science History, Science News

Photos of Elizabeth H. Blackburn, Carol W. Greider, and Jack W. Szostak

On Oct. 5, 2007, three American researchers -- Elizabeth H. Blackburn, Carol W. Greider, and Jack W. Szostak -- were awarded the Nobel Prize in Physiology or Medicine. This marks a milestone because it’s the first time two women have shared a Nobel prize. In a recent online interview, Blackburn said the honor for her and Greider is “a hopeful sign” for women. In the future, she said, people will say, “Oh yes, it’s not too unusual to have women getting Nobel prizes. Two got one this year. I hope it becomes very normal.” You can listen to the scientists’ reactions to The Call announcing their award at the Nobel Web site.

Their story begins with chromosomes, the giant complexes of DNA and proteins found in our cells. When cells divide, they make a copy of each chromosome, so the daughter cell receives a full complement of DNA. The enzymes that control this process can’t quite copy the chromosome all the way to the end, so a little bit of the chromosome is lost every time a cell divides. Enter the telomere and our Nobelists’ research.

Telomeres are short regions of repetitive DNA that sit at the ends of chromosomes but don’t encode any genes. When a cell divides, the telomeres get shorter, not the business part of the chromosomes. With each cell division, the telomeres get shorter. Scientists believe that this telomere shortening is in part responsible for the limited lifespan of most cells. However, some cells, including stem cells that live for the life of an organism, can replace telomeres through the action of the enzyme telomerase.

Telomerase is turned off in most cells, but it’s reactivated in many cancer cells. This allows the cancer cells to replicate many more times than normal. This has opened the possibility of treating cancer by zeroing in on telomerase. Clinical trials are under way to evaluate vaccines directed against cells with elevated telomerase activity.

The Nobelists’ research also opens up a wide range of investigations into the roles that telomeres and telomerase play in aging. This is because as we age, more and more of our cells have shortened telomeres. Some cells with short telomeres die while others “senesce,’ which means they remain in place but can’t divide and have reduced functional capacity. If we have too many senescent cells, normal processes are less efficient, and repairing even minor damage becomes difficult.

Nobel Prize 2009

http://nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html