TERT

Telomerase reverse transcriptase (TERT) is the catalytic subunit of the enzyme telomerase, which, along with the telomerase RNA component (TERC), is responsible for the replication of telomeres in eukaryotic cells. This enzyme plays a crucial role in cellular aging and has implications in aging-related diseases and cancer.

Function

TERT is a reverse transcriptase that adds DNA sequence repeats ("TTAGGG" in all vertebrates) to the 3' end of DNA strands in the telomere regions, which are found at the ends of chromosomes. The enzyme activity of TERT is essential for telomeres because it helps maintain the length of telomeres, which otherwise shorten with each cell division. Without adequate TERT activity, critical DNA is lost with each replication, eventually leading to cell death or senescence.

Clinical Significance

Alterations in TERT expression and function have been linked to several human diseases. Over-expression of TERT has been observed in various types of cancers, suggesting that it may play a role in cellular immortality, a hallmark of cancer cells. Conversely, mutations that reduce TERT activity are associated with disorders such as dyskeratosis congenita, which involves premature aging and a higher risk of cancer due to inadequate maintenance of telomeres.

Genetic Regulation

The regulation of TERT is complex and involves multiple mechanisms, including transcriptional control, epigenetic modifications, and alternative splicing. The promoter region of the TERT gene contains several binding sites for transcription factors that either activate or repress its expression, depending on the cell type and conditions.

Research and Therapeutic Potential

Due to its central role in aging and cancer, TERT is a significant target for drug development. Inhibitors of TERT are being studied for their potential to limit cancer cell growth by shortening telomeres. Conversely, activation of TERT has potential therapeutic implications in age-related diseases, tissue regeneration, and stem cell therapies.

See Also

• Telomere
• Telomerase
• Oncogene
• Senescence