端粒酶是一種核糖核蛋白聚合酶，通過添加端粒重復序列TTagg來維持端粒末端。這種酶由一種具有逆轉錄酶活性的蛋白質成分（由該基因編碼）和一種作為端粒重復模板的RNA成分組成。端粒酶的表達在細胞衰老中起作用，因為它通常在出生后的體細胞中被抑制，導致端粒逐漸縮短。體細胞端粒酶表達的放松調控可能與腫瘤發生有關。對小鼠的研究表明端粒酶也參與染色體修復，因為端粒重復序列的從頭合成可能發生在雙鏈斷裂處。另外，還發現了編碼端粒酶逆轉錄酶不同亞型的剪接變體；一些變體的全長序列尚未確定。在這個位點的選擇性剪接被認為是調節端粒酶活性的一種機制。
Telomerase is a ribonucleoprotein polymerase that maintains telomere ends by addition of the telomere repeat TTAGGG. The enzyme consists of a protein component with reverse transcriptase activity, encoded by this gene, and an RNA component which serves as a template for the telomere repeat. Telomerase expression plays a role in cellular senescence, as it is normally repressed in postnatal somatic cells resulting in progressive shortening of telomeres. Deregulation of telomerase expression in somatic cells may be involved in oncogenesis. Studies in mouse suggest that telomerase also participates in chromosomal repair, since de novo synthesis of telomere repeats may occur at double-stranded breaks. Alternatively spliced variants encoding different isoforms of telomerase reverse transcriptase have been identified; the full-length sequence of some variants has not been determined. Alternative splicing at this locus is thought to be one mechanism of regulation of telomerase activity.