Telomerase and its extracurricular activities.

The classical activity of telomerase is to synthesize telomeric repeats and thus maintain telomere length, which in turn ensures chromosome stability and cellular proliferation. However, there is growing evidence that implicates telomerase in many other functions that are independent of TERC being used as its template. Telomerase has an RNA-dependent RNA polymerase (RdRP) activity in the mitochondria. Other than viral RdRPs, it is the only RNA-dependent RNA polymerase that has been identified in mammals. It also plays a role in the Wnt signaling pathway by acting as a transcriptional modulator. Telomerase acts as a reverse transcriptase independent of its core subunit, TERC. Studies indicate that telomerase is also involved in apoptosis and DNA repair.