Video: What are telomeres and how do they protect our cells?

Telomeres Explained video image

What are telomeres? Telomeres are protective caps, found at the ends of our chromosomes. This is the first in a short series of videos where we explore telomeres, telomere length and telomerase, as well as the impact they have on our health and aging.

Telomeres are thought to play a major role in aging by limiting the number of times most of the cells in our body can divide. They help protect our genome and defend our bodies from developing cancer.

Our telomeres can have anywhere between a few hundred to thousands of repeats all with the same distinctive DNA sequence — TTAGGG. The repeats bind a set of proteins called shelterin and together they protect the DNA by forming a closed telomere cap.

Every time our cells divide, DNA repeats are lost so our telomeres shorten, like a slowly burning candle. Too-short — or uncapped telomeres — signal to the cell that it’s time to retire. The retiring cells stay in a resting state called senescence, meaning they stop dividing, or they undergo programmed cell death.

When telomeres are too short, it can be an indicator that the cells have accumulated too much damage or have divided too many times – and have possibly acquired dangerous mutations. Telomere loss can therefore be an important mechanism to suppress tumor growth.

This video is part of a series where we explore telomeres, telomere length and telomerase, as well as the impacts they have on our health and aging.

For more information on, and to watch, the next episode on how telomere shortening affects aging, click here.

RepeatDx is a leading clinical laboratory for telomere length testing. You can find out more about telomere length testing with RepeatDx here.

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  1. de Lange, T. Shelterin-Mediated Telomere Protection. Annu Rev Genet 52, 223-247, doi:10.1146/annurev-genet-032918-021921 (2018).
  2. Aubert, G., Baerlocher, G. M., Vulto, I., Poon, S. S. & Lansdorp, P. M. Collapse of telomere homeostasis in hematopoietic cells caused by heterozygous mutations in telomerase genes. PLoS Genet 8, e1002696, doi:10.1371/journal.pgen.1002696 (2012).