telomeres and the 2009 Nobel Prize

3 American scientists, Elizabeth H. Blackburn, Carol W. Greider and Jack W Szostak, won the 2009 Nobel Prize in Medicine for their research into telomeres and telomerase that led to new insights into aging, cancers and some inherited disease and could lead to new treatments for the diseases.

Their work solved one of the mysteries of how cells duplicate without losing pieces of the chromosomes. Chromosomes are strands of DNA that carry genes. Blackburn found that at the end of each of the chromosomes was the repeating DNA sequence – CCCCAA. Szostak had developed mini-chromosomes and found that each time the cells divided, the mini-chromosomes degraded and eventually vanished completely.

Blackburn and Szostak collaborated in 1980 and made mini-chromosomes with the CCCCAA sequences at either end. They found that when these were injected into yeast, the DNA sequence protected the chromosomes when they were copied. They called the caps “telomeres”. In 1984, Greider, Blackburn’s student, discovered the enzyme, “telomerase”, that makes telomeres.

Further studies discovered that healthy telomeres delayed the aging process in cells, prompting research into anti-aging treatments. Related studies found that defective telomeres had affected the division of bone marrow stem cells and overactive telomerase was associated with the development of cancer.

However, a member of the Prize Committee said that large questions remain to be answered about the working of telomeres and telomerase. Merck, a drug company, is currently running a trial of a cancer vaccine designed to train the body to attack tumor cells that produce telomerase.

Exercise can make you younger

A new study based on the analysis of questionnaires of more than 2400 twins found that physically active adults are biologically younger than inactive ones - they have longer telomeres that are the caps at the end of the chromosomes. Telomeres tend to get shorter as people age and are used as an indicator of a peson's biological age.


The research team said the "differences in telomere length between active and inactive individuals cannot be explained by variations in genes, smoking, BMI and socioeconomic status", and the findings "could be used by clinicians to promote the potentially anti-aging effect of regular exercise". The study is published in the Archives of Internal Medicine, 28th issue.

In an editorial in the same issue, an expert said there could be other factors responsible for the biological differences between active and sedentary people, but the findings provide the evidence that telomere length might be targeted in studying ageing outcomes.

Source: "The Association Between Physical Activity in Leisure Time and Leukocyte Telomere Length."Arch Intern Med. 2008;168(2):154-158. ( full text via Athens)