端粒酶是一种核糖核蛋白聚合酶，通过添加端粒重复序列TTagg来维持端粒末端。这种酶由一种具有逆转录酶活性的蛋白质成分（由该基因编码）和一种作为端粒重复模板的RNA成分组成。端粒酶的表达在细胞衰老中起作用，因为它通常在出生后的体细胞中被抑制，导致端粒逐渐缩短。体细胞端粒酶表达的放松调控可能与肿瘤发生有关。对小鼠的研究表明端粒酶也参与染色体修复，因为端粒重复序列的从头合成可能发生在双链断裂处。另外，还发现了编码端粒酶逆转录酶不同亚型的剪接变体；一些变体的全长序列尚未确定。在这个位点的选择性剪接被认为是调节端粒酶活性的一种机制。
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.
第三启动子突变是激活的，通常在第三启动子区域的两个热点处发现，在翻译起始位点上游出现124和146碱基对（hg19）。这些热点被称为C228T和C250T，在许多癌症类型中都有观察到，在胶质母细胞瘤（83%）、黑色素瘤（71%）、膀胱癌（66%）和肝细胞癌（47%）中的发病率特别高。这两个突变通常是杂合子，相互排斥，导致与ETS结合域的相似性增加，并可能作为与ETS转录因子的结合位点。这些突变被认为是肿瘤发生的早期事件，有助于细胞的永生。在髓母细胞瘤、甲状腺癌、泌尿生殖道癌、黑色素瘤和喉部肿瘤中观察到这些突变患者的总生存率下降。这些突变的存在也被证明可以预测肝癌和脑膜瘤的恶性/癌前结节。
TERT promoter mutations are activating and commonly found at two hotspots within the TERT promoter region which occur 124 and 146 base pairs (hg19) upstream of the translation start site. These hotspots, termed C228T and C250T are observed in many cancer types and have a particularly high prevalence in glioblastoma (83%), melanoma (71%), bladder cancer (66%) and hepatocelluar carcinoma (HCC) (47%). The two mutations are usually heterozygous and mutually exclusive and result in an increased similarity to an ETS binding domain and may act as a binding site to an ETS transcription factor. These mutations are thought to be early events in tumorgenesis and aid in cellular immortality. Decreased overall survival in patients with these mutations have been observed in medulloblastoma, thyroid cancer, urogenital cancer, melanoma, and laryngeal tumors. The presence of these mutations has also been shown to be predictive of malignant/premalignant nodules in HCC and meningiomas.
| Chr. | Start | Stop | Ref. s | Var. Bases |
| 5 | 1295161 | 1295373 | ||
| Transcript | ||||
| ENST00000310581.5 | ||||