DNA polymerase gamma, catalytic subunit (human) (POLG)

DNA polymerase gamma is the sole DNA polymerase responsible for replication and repair of mitochondrial DNA in human cells. It functions as a heterotrimeric holoenzyme composed of a single catalytic subunit (encoded by the POLG gene) and a dimer of accessory subunits; the catalytic subunit has both polymerase (replicative) and 3’-5’ exonuclease (proofreading) activities. Proper function of this enzyme is essential for maintenance of mitochondrial genome stability, energy metabolism, and cellular homeostasis. Mutations in POLG or inhibition by certain antiviral drugs (notably NRTIs for HIV) can result in mitochondrial DNA depletion or multiple deletions, contributing to a range of mitochondrial diseases with neurological, hepatic, muscular, or gastrointestinal manifestations. This enzyme is therefore both a key biomolecule for normal mitochondrial function and a clinically important drug target and toxicity mediator.

Other names

DNA polymerase γpolymerase gammaPol γPOLGmitochondrial DNA polymeraseDNA polymerase subunit gammapolGDNA polymerase gamma catalytic subunitmitochondrial DNA polymerase gamma

Inhibition of polymerase activity via incorporation of nucleoside analogs, Competitive inhibition, Chain termination during replication