Telomeres Delay Aging of Cells

A telomere is a region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes.

Scientists began to investigate what role the telomere might play in the cell. Jack William Szostak a Canadian American biologist and his group identified yeast cells with mutations that led to a gradual shortening of the telomeres. Such cells grew poorly and eventually stopped dividing.

In both cases, this led to premature cellular aging – senescence. In comparison, functional telomeres prevented chromosomal damage and therefore delayed cellular aging. Later on, Greider and her team showed that the aging of human cells is also delayed by telomerase. It is now recognised that the DNA sequences in the telomere attracts proteins which form a protective cap around the fragile ends of DNA strands.

Most normal cells do not divide frequently, therefore their chromosomes are not at risk of shortening and they do not require high telomerase activity. In contrast, cancer cells have the ability to divide infinitely and yet preserve their telomeres. So, how do they escape cellular aging?

One explanation became apparent with the findings that cancer cells often have increased telomerase activity. It was therefore proposed that cancer might be treated by eradicating telomerase. Some inherited diseases are now known to be caused by telomerase defects, including certain forms of congenital aplastic anemia, in which insufficient cell divisions in the stem cells of the bone marrow lead to severe anemia.

Certain inherited diseases of the skin and the lungs are also caused by telomerase defects. The discoveries by Blackburn, Greider and Szostak have added a new dimension to our understanding of the cell, shed light on disease mechanisms, and have stimulated the development of potential new therapies.

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Branka Duric

Beauty Editor experienced in writing on Fashion, Beauty, Health & Skincare.