Human telomerase (Telomerase (hTERT/hTR complex))

**Human telomerase** is a ribonucleoprotein enzyme complex composed primarily of a catalytic protein subunit, **telomerase reverse transcriptase (hTERT)**, and an RNA component **(hTR, also known as hTERC)**, along with several accessory proteins (e.g., dyskerin, GAR1, NHP2, NOP10, TCAB1)[1][4][5][7]. Its primary function is to add repetitive nucleotide sequences (TTAGGG in humans) to the ends of linear chromosomes (telomeres), using its intrinsic RNA as a template for DNA synthesis, thus maintaining telomere length[3][5][7]. The enzyme is typically active in germ cells, stem cells, and most cancer cells, but is low or absent in most somatic cells. This activity is critical for unlimited replication potential in cancer, making telomerase a key therapeutic target in oncology[3][7]. Human telomerase structure is bilobal, with the catalytic core (hTERT and hTR) responsible for reverse transcription and a complex of accessory proteins for assembly and stability[1][3][4]. Therapeutic inhibition of telomerase aims to induce replicative senescence or apoptosis in cancer cells, but the approach is challenged by safety concerns related to effects on normal proliferative tissues[7].

Other names

TelomeraseHuman telomerase reverse transcriptase (hTERT)Telomerase RNA component (hTR or hTERC)Terminal transferase

Inhibition of telomerase catalytic activity (e.g., competitive binding to active site); Blocking telomerase-telomere interaction; Targeting the RNA component of telomerase for degradation or inhibition