Summary
A ribonucleoprotein enzyme that extends telomeres in stem and cancer cells using an RNA template.
In depth
Telomerase (TERT protein plus TERC RNA) adds TTAGGG repeats using its internal RNA template, offsetting shortening. It is active in germ cells, stem cells and most cancers but silent in most somatic cells.
Elizabeth Blackburn, Carol Greider and Jack Szostak got the Nobel Prize in 2009.
Telomerase solves the end-replication problem for chromosomes. Telomerase reverse transcriptase uses TERC RNA as a template for each repeat, then translocates and repeats; the ends form a T-loop protected by shelterin. Mice have long telomeres and active telomerase in many tissues, which partly explains why they get tumours easily and live shorter.
Telomerase reactivation (often by TERT promoter mutations) is found in most cancers, so inhibitors such as imetelstat have been tested, and telomerase-based approaches are considered for ageing, with cautions because of cancer risk. Telomere length is influenced by inheritance, age and stress.
Example: dyskeratosis congenita and aplastic anaemia can be caused by mutations in TERT or TERC.
Frequently asked questions
What is Telomerase?
A ribonucleoprotein enzyme that extends telomeres in stem and cancer cells using an RNA template.
Which area of biology covers Telomerase, and how advanced is it?
Telomerase is one of the 52 topics in Molecular Biology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Homologous Recombination, Reverse Transcription, Gene Expression.
Can you give an example of Telomerase?
Some cancers use ALT, a recombination-based alternative.
What should I learn before Telomerase?
Work through the Beginner topics in Molecular Biology first, such as Central Dogma, DNA Replication, Base Pairing, then return to Telomerase. Advanced topics assume the Intermediate vocabulary.
What topics are related to Telomerase?
The closest topics to Telomerase are Homologous Recombination, Reverse Transcription, Gene Expression, Mutation and Repair Link. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Telomerase?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Telomerase. To practise the whole of Molecular Biology, use the Molecular Biology quiz.
How is Telomerase different from Homologous Recombination?
Telomerase: A ribonucleoprotein enzyme that extends telomeres in stem and cancer cells using an RNA template. Homologous Recombination: An accurate repair pathway and meiotic mechanism exchanging DNA between similar sequences using RAD51. Read both side by side and note what each one explains.
How should I study Telomerase step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Homologous Recombination and explain the difference aloud. Finally, take the Molecular Biology quiz and come back to this page for any question you miss.