Telomerase (端粒酶)

Telomerase is a DNA polymerase that extends the 3' ends of chromosomes by processively synthesizing multiple telomeric repeats. It is a unique ribonucleoprotein (RNP) containing a specialized telomerase reverse transcriptase (TERT) and telomerase RNA (TER) with its own template and other elements required with TERT for activity (catalytic core), as well as species-specific TER-binding proteins important for biogenesis and assembly (core RNP); other proteins bind telomerase transiently or constitutively to allow association of telomerase and other proteins with telomere ends for regulation of DNA synthesis.

Telomerase activity is responsible for the maintenance of chromosome end structures (telomeres) and cancer cell immortality in most human malignancies, making telomerase an attractive therapeutic target. Indeed, a telomerase inhibitor is expected to provide a therapeutic benefit in most cancers while having little side-effects. The adult stem cells that express telomerase in normal tissues divide slowly and have long telomeres, therefore they should be less impacted by telomerase inhibition than the cancer cells which divide rapidly and usually possess short telomeres.