Lexicon
Telomeres
Also known as Telomere
Definition
Telomeres are specialized nucleoprotein structures at the ends of linear chromosomes that prevent the activation of DNA damage response and repair pathways. [1] Telomeric DNA consists of long stretches of short TTAGGG repeats that are conserved across most eukaryotes including humans. [2] Telomere shortening occurs with ageing and may contribute to associated maladies such as neurodegeneration, cancer and lung dysfunction. [3]
How it works
Telomeres shorten following cell division in the absence of telomerase activity, and when they become critically short or damaged a DNA damage response is activated, triggering cellular senescence or death. [3] At least a few hundred nucleotides of telomere repeats must cap each chromosome end to avoid activation of DNA repair pathways, and apoptosis or cellular senescence is triggered when too many uncapped telomeres accumulate. [4] The telomerase enzyme counteracts telomeric DNA loss by de novo addition of telomeric repeats onto chromosomal ends, and germline and stem cells maintain significant telomerase activity while its downregulation in somatic cells drives progressive shortening. [2]
Connected concepts
How it's measured
Telomere-length quantification methods have improved greatly in accuracy and sensitivity since the development of the conventional telomeric Southern blot. [5] Strategies for measuring telomere length have expanded to include analyzing genome-sequence data and capitalizing on genomic loci that associate with telomere length, but there is no gold standard for measuring it. [6] [7] Leukocyte telomere length is the most commonly assessed measure, yet because of wide interindividual variability a single assessment in an individual does not reliably report on a biological aging process. [6]
What levels mean
Short telomeres confer risk of degenerative diseases and are considered a biomarker for worsening health and early death. [8] [9] The balance of evidence indicates that short leukocyte telomeres confer a risk for atherosclerotic cardiovascular disease
Community knowledge
## Telomeres As A Hallmark Of Aging
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- 1.Revy P, Kannengiesser C, Bertuch AA. Genetics of human telomere biology disorders. Nat Rev Genet · 2023
- 2.Dunn PL, Logeswaran D, Chen JJ. Telomerase-Mediated Anti-Ageing Interventions. Subcell Biochem · 2024
- 3.Jones-Weinert C, Mainz L, Karlseder J. Telomere function and regulation from mouse models to human ageing and disease. Nat Rev Mol Cell Biol · 2025
- 4.Aubert G, Lansdorp PM. Telomeres and aging. Physiol Rev · 2008
- 5.Canela A, Klatt P, Blasco MA. Telomere length analysis. Methods Mol Biol · 2007
- 6.Yin H, Pickering JG. Telomere Length: Implications for Atherogenesis. Curr Atheroscler Rep · 2023
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