This year’s Nobel Prize in Physiology or Medicine has been awarded to three scientists who were instrumental in solving one of the enigmas of DNA replication, namely the problem of Replication of the entire Chromosome and prevention of degradation. The Nobel committee at Karolinska Institutet decided to jointly award the 2009 Nobel prize to Elizabeth H. Blackburn, Carol W. Greider and Jack W. Szostak for their Discovery of “how chromosomes are protected by telomeres and the enzyme telomerase1

Dr. Elizabeth Blackburn
Dr. Elizabeth Blackburn

Now, what are these Telomeres? They are nothing but the special cap like structures at the ends of our tightly packed chromosomes. Elizabeth B. And Jack S. Discovered that special sequences in these telomeres prevented the degradation of chromosomes while they were being replicated. It followed very logically then, that if there are telomeres then there must be definitely some enzyme responsible for their synthesis. Working on this premise, Elizabeth B. and Carol G went to identify the unique enzyme, Telomerase.

Dr. Carol Grieder

Dr. Carol Grieder

What interests me the most is the putative link between Telomeres and the processes of Senescence (Aging) and Cancer. Scientists have long known that the presence of Telomeres somehow prevents destruction of DNA. The question was, How? This process has now been elucidated by this year’s Nobel Laureates. The enzyme Telomerase synthesises telomeres and helps maintain the Chromosome intact. This was proved by studying the simple yeast and cells of the unicellular organism Tetrahymena. Yeast cells studied by Jack S and his group were mutants for the Telomere region. Progressive cell divisions resulted in the shortening of this region. Over several generations the cells were unable to divide any further. Similarly, Blackburn’s Studies on Tetrahymena that carried a mutation in the RNA of the telomerase enzyme also yielded similar results.

MicroscopeIt was now clear that cells that have increased Telomerase activity are likely to live longer and this was exactly what was observed in the case of one of the most deadly diseases, Cancer. Cancer cells have increased activity of Telomerase and this could therefore be one probable way of designing vaccines targeted at cells over expressing Telomerase. Efforts are underway to synthesise such vaccines.

Another interesting aspect of Telomeres is their connection to ageing. Intact telomeres are essential for the normal health of the cell and degradation leads to senescence of the cell. Scientists postulated that it was not only the cell that aged but the entire organism. Of course, today we recognise aging to be a complex process that has many varied and complex contributing factors and the telomere/telomerase duo is just one of them.

Dr. Jack Szostak

Dr. Jack Szostak

The laureates’ work underlines our quest towards understanding the underlying mechanisms that might be responsible for the deadly cancer on the one hand and the process of aging on the other. While remedies for cancer are urgent, some people might argue that prevention of the aging process is cosmetic and vain and against the laws of nature. I would have agreed whole heartedly had it not been for some freakish quirks on our genes that result in the rare but deadly Progeria also known as the Hutchinson-Gilford Progeria Syndrome. This is a disease that causes premature aging, and patients rarely survive beyond 13 years of age. Another such ailment is Dyskeratosis congenita. If research into halting the aging process can provide treatments for such nightmarish conditions then I say, go for it. After all, once a particular result is out it for us to take a rational decision on how the result is to be used. So would we rather use it to live forever or to cure people suffering from a quirk of their genes is a question we all need to ask ourselves.

About the Laureates:

Elizabeth H. Blackburn was born in 1948 in Hobart, Tasmania, Australia. She is a PhD from the University of Cambridge, England. She carried out postdoctoral research at Yale University in USA. She is a professor of biology and physiology at the University of California, San Francisco. Please check out this site for some detailed information on this Author’s work.

Carol W. Greider was born in 1961 in San Diego, California, USA. She completed her PhD under Blackburn. She was appointed as Professor in the Molecular Biology and Genetics Department at the Johns Hopkins University School of Medicine in Baltimore in 1997. More on this Author.

Jack W. Szostak was born in 1952 in London, UK.  He grew up in Canada & received his PhD at the Cornell University in New York, in 1977. He has been associated with the Harvard Medical School since 1979; currently holds the post of professor of genetics at Massachusetts General Hospital in Boston & is affiliated with the Howard Hughes Medical Institute. Check out this wonderful Site for further details.

References:

  1. http://nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html
  2. http://nobelprize.org/nobel_prizes/medicine/laureates/2009/bild_press_eng.pdf

References for Images:

1. discovermagazine.com/2007/dec/blackburn

2. www.pnas.org/…/102/23/8077/F1.expansion.html

3. www.expressgenes.com/Frontier08/main.html