Telomerase – Elixir of youth or something more Nobel?

Last week, the Nobel Prize in physiology or medicine was awarded to Tazmanian-born US scientist Elizabeth H. Blackburn, Australia's first woman Nobel Prize laureate, and her two American colleagues Carol W. Greider and Jack W. Szostak for their efforts in the area of genetics and cell biology and, more specifically, for their discoveries relating to telomeres and telomerase.

Together, the trio have been recognised for their significant research into basic cell biology and the contribution it has made to our understanding of how each generation carries a genetic code stored in DNA and is meticulously organised in chromosomes. Perhaps even more groundbreaking, is that this research has also identified that the enzyme telomerase – first isolated and characterised in 1984 while Greider was a graduate student in Blackburn's lab – is one of the causes of cell mutation, providing a catalyst for growth of 85 percent of cancers.

As well as offering insights into cancer, the research has also pinpointed that telomeres – the ends of the chromosomes that are formed by telomerase – incorporate a unique DNA sequence that protects the cell against degradation as it replicates.

Every time a cell divides, telomerase add telomeres sequences to the ends of chromosomes to help their own cell's DNA to read to the end of the chromosomes, in order to make up for the shortening during cell division. If the telomeres are shortened, cells subsequently age and, without telomerase, cells will stop dividing and will ultimately die. Conversely, if telomerase activity is high, telomere length is maintained, and cellular ageing is delayed. This is the case in cancer cells, where overactive telomerase allows them to continue dividing and can, therefore, be considered to have eternal life. The trio's research thereby offers insights into ageing and has earned telomerase the title of the “immortality enzyme”.

Sound confusing? Well, the story gets even more complex...

Whilst the repairing or 'anti-ageing' properties of telomerase might seem rather beguiling, caution should be urged in exploiting the enzyme's growth-potential fully, as it is precisely this over-activity that cancers thrive on. In contrast, certain inherited diseases are characterised by a defective telomerase, resulting in damaged cells. Dyskeratosis congenita, for example, a rare genetic skin condition characterised by symptoms that resemble premature ageing, such as abnormal skin pigmentation, is said to be caused by a faulty telomere-maintenance system.

Laying aside the contentious issues of immortality and disease raised by the discovery of the telomerase enzyme, the research conducted by Blackburn, Greider and Szostak is considered to have important implications for the development of experimental cancer therapies that block the activity of telomerase. So, as well as adding a new dimension to our understanding of the cell, there is evidence to suggest that these findings may, in time, lead to a vaccine that targets telomerase, which could, incredibly, help fight certain kinds of cancer.

You are not currently signed in, please sign in or register to post a comment