cell-biology
Telomerase
Definition
Telomerase is a ribonucleoprotein reverse transcriptase enzyme composed of a catalytic subunit (TERT) and an RNA template component (TERC) that maintains telomere length by adding repetitive TTAGGG nucleotide sequences to chromosome ends. In most somatic cells, telomerase activity is repressed, leading to progressive telomere shortening with each cell division and eventual replicative senescence. Telomerase reactivation has been a focus of aging research, with the tetrapeptide epithalon (Ala-Glu-Asp-Gly) shown in preclinical studies to activate telomerase gene expression in human somatic cells.