Telomeres and aging.

Telomeres (the TTAGGG repetitive DNA at the ends of linear chromosomes) are part of the 3D spatial organization of the nuclear genome. Long-range 3D chromatin interactions also establish specific patterns of regulated gene expression. An emerging area of interest is the role of telomere 3D looping with interstitial telomeric sequences (ITS) through interactions with telomere shelterin proteins. Telomeres form interstitial telomere loops (ITL) that interact with ITS and modify gene expression at distal genomic regions. Human laminopathies and telomeropathies often correlate with short telomeres. Since telomeres progressively shorten with increased turnover and chronological age in dividing somatic cells, ITLs may also change and have functional roles in normal and pathophysiological processes. Overall, telomeres help stabilize the nuclear genome with high fidelity throughout early adult life but diminish in post-reproductive age-associated pathology.