Telomerase Reverse Transcriptase

Telomerase reverse transcriptase (abbreviated to TERT, or hTERT in humans) is a catalytic subunit of the enzyme telomerase, which together with the telomerase RNA component (TERC), are the most important components of the telomerase complex.

Telomerases are part of a distinct subgroup of RNA-dependent polymerases. Telomerase lengthens telomeres in DNA strands, thereby allowing senescent cells that would otherwise become postmitotic and undergo apoptosis to exceed the Hayflick limit and become potentially immortal, as is often the case with cancerous cells. Specifically TERT is responsible for catalyzing the addition of nucleotides in a TTAGGG sequence to the ends of a chromosome’s telomeres. This addition of repetitive DNA sequences prevents degradation of the chromosomal ends following multiple rounds of replication.

hTERT absence (usually as a result of a chromosomal mutation) is associated with the disorder Cri du chat.