POLG2

This gene encodes the processivity subunit of the mitochondrial DNA polymerase gamma. The encoded protein forms a heterotrimer containing one catalytic subunit and two processivity subunits. This protein enhances DNA binding and promotes processive DNA synthesis. Mutations in this gene result in autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions

Full Name

POLG2

Function

Mitochondrial polymerase processivity subunit. It regulates the polymerase and exonuclease activities promoting processive DNA synthesis. Binds to ss-DNA.

Biological Process

DNA repairIEA:InterPro
DNA-templated DNA replicationManual Assertion Based On ExperimentIDA:UniProtKB
In utero embryonic developmentIEA:Ensembl
Mitochondrial DNA replicationManual Assertion Based On ExperimentIDA:ComplexPortal
Mitochondrion morphogenesisIEA:Ensembl
Positive regulation of DNA-directed DNA polymerase activityManual Assertion Based On ExperimentIDA:UniProtKB
Respiratory electron transport chainIEA:Ensembl

Cellular Location

Mitochondrion

Involvement in disease

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 4 (PEOA4):
A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.
Mitochondrial DNA depletion syndrome 16, hepatic type (MTDPS16):
An autosomal recessive disorder characterized by poor feeding, difficulty breathing, abdominal distention, an abnormal carnitine profile, metabolic acidosis and hepatic failure in the neonatal period. Severe mtDNA depletion is observed in liver and muscle biopsies.
Mitochondrial DNA depletion syndrome 16B, neuroophthalmic type (MTDPS16B):
An autosomal recessive disorder characterized by childhood onset of progressive neuroophthalmic manifestations with optic atrophy, mixed polyneuropathy, spinal and cerebellar ataxia, and generalized chorea associated with mtDNA depletion.