Telomereja

Telomereja, commonly referred to as telomeres in English, are specialized structures at the ends of linear chromosomes that protect genetic information during cell division. In humans they consist of repeated DNA sequences (TTAGGG) bound by a multi-protein complex called shelterin, which helps cap chromosome ends and promotes the formation of a protective t-loop that hides the ends from DNA damage responses.

During DNA replication, the cellular machinery cannot fully copy chromosome ends, leading to progressive shortening of telomeres with each division. When telomeres become critically short, cells may enter replicative senescence or undergo apoptosis, linking telomere length to aging at the tissue level. Telomere dynamics are influenced by inheritance, tissue type, and environmental factors, with lifestyle and stress able to modulate shortening rates.

Telomere maintenance is powered in part by telomerase, a ribonucleoprotein reverse transcriptase that adds telomeric repeats to ends. Telomerase is active in germ cells, many stem cells, and a majority of cancer cells, but is repressed in most somatic cells, contributing to limited proliferative capacity outside the germline.

Key shelterin components include TRF1, TRF2, POT1, TIN2, TPP1, and RAP1; together they regulate elongation, protect chromosome ends, and prevent inappropriate DNA repair. Clinically, telomere biology disorders such as dyskeratosis congenita illustrate the importance of proper telomere maintenance and can present with bone marrow failure, lung disease, and mucocutaneous symptoms.

Telomere length is measured by methods such as terminal restriction fragment analysis, quantitative PCR, and qFISH. While telomere length is a useful biomarker in aging research, it is not a sole predictor of health, and interventions to influence telomere dynamics remain an active, cautious area of study.