Telomerase enzyme

Definition

Telomerase is a specialized enzyme that adds repetitive nucleotide sequences to the ends of chromosomes, known as telomeres. By extending these telomeres, telomerase plays a critical role in maintaining chromosomal stability and cellular longevity, which are essential factors in oncogenic transformation and cancer development.

5 Must Know Facts For Your Next Test

1. Telomerase is typically active in stem cells, germ cells, and many cancer cells, allowing them to divide indefinitely.
2. In most somatic cells, telomerase activity is low or absent, leading to gradual telomere shortening with each cell division.
3. Cancer cells often reactivate telomerase, which contributes to their uncontrolled growth and the immortality of these cells.
4. The mechanism by which telomerase extends telomeres involves the reverse transcription of a template RNA molecule that is part of the enzyme.
5. Therapeutic strategies targeting telomerase are being explored as potential treatments for various cancers by limiting cancer cell proliferation.

Review Questions

• How does the function of telomerase relate to cellular aging and the process of oncogenic transformation?
  • Telomerase functions to extend the telomeres at the ends of chromosomes, which counters the natural shortening that occurs during cell division. In normal somatic cells, this shortening eventually leads to cellular senescence, limiting the number of divisions a cell can undergo. However, in cancer cells, reactivation of telomerase allows for indefinite divisions and contributes to oncogenic transformation by providing a mechanism for these cells to bypass normal growth restrictions.
• Discuss the implications of telomerase activity in cancer therapy and how targeting this enzyme might provide therapeutic benefits.
  • Targeting telomerase activity in cancer therapy is based on the understanding that many cancer cells rely on this enzyme for their continued growth and division. By inhibiting telomerase, it may be possible to induce senescence or apoptosis in cancer cells, thereby limiting tumor growth. Such approaches could potentially lead to more effective treatments by selectively targeting cancerous tissues while minimizing effects on normal cells that have low or absent telomerase activity.
• Evaluate the role of telomeres and telomerase in the broader context of cellular biology and their impact on human health beyond cancer.
  • Telomeres and telomerase play crucial roles not only in cancer biology but also in overall cellular health and aging processes. Shortened telomeres are associated with various age-related diseases and conditions, including cardiovascular disease and neurodegenerative disorders. Understanding how telomerase can be manipulated provides insights into potential anti-aging therapies and regenerative medicine, opening avenues for improving healthspan and addressing age-related decline.

Related terms

Telomeres: Protective caps located at the ends of chromosomes that prevent them from deteriorating or fusing with neighboring chromosomes.

Cellular Senescence: A state in which cells cease to divide and grow, often triggered by critically short telomeres, contributing to aging and tissue regeneration limitations.

Oncogenes: Genes that have the potential to cause normal cells to become cancerous when mutated or expressed at high levels.