“Whoa! It's like Spotify but for academic articles.”

Instant Access to Thousands of Journals for just $40/month

Get 2 Weeks Free

Telomeres and telomerase in ageing and cancer



Telomeres lie at the ends of human chromosomes and contain long tandem repeats of a simple nucleotide sequence. Because DNA replication cannot proceed to the very end of chromosomes, copies of these repeats are lost at each cell division. If the telomeres shorten below a critical length, the cells will eventually die as a result of genomic instability. Aging cells usually avoid death by entering senescence before the critical telomere length is reached. Malignantly transformed, immortal cells overcome senescence but they must still avoid the final, critical shortening of telomeres to survive. In the vast majority of cases, tumor cells achieve this by activating the telomerase enzyme, a ribonucleoprotein complex which repairs the end of chromosomes and prevents telomere shortening. Normal mortal cells do not normally express telomerase, although some stem cell populations which must regenerate thought the life span of the organism, retain enzyme activity. Cellular senescence can be overcome by inducing telomerase expression in mortal cells, firmly establishing the role of telomere length in the senescence signaling pathway. In tumor cells, the evidence of a role for telomerase in immortality is still largely correlative, with 80–90% of tumors expressing telomerase activity. To establish whether telomerase activity is important in maintaining the malignant phenotype, attempts have been made to inactivate it in tumor cells, using a variety of approaches, where there is evidence that disrupting telomerase function can result in the induction of apoptosis. The background and implications of these observations is discussed.



AGESpringer Journals

Published: Apr 1, 1999

DOI: 10.1007/s11357-999-0007-2

Free Preview of First Page

Loading next page...

You're reading a free preview. Subscribe to read the entire article.

And millions more from thousands of peer-reviewed journals, for just $40/month

Get 2 Weeks Free

To be the best researcher, you need access to the best research

  • With DeepDyve, you can stop worrying about how much articles cost, or if it's too much hassle to order — it's all at your fingertips. Your research is important and deserves the top content.
  • Read from thousands of the leading scholarly journals from Springer, Elsevier, Nature, IEEE, Wiley-Blackwell and more.
  • All the latest content is available, no embargo periods.