POLG2
Function
Accessory subunit of DNA polymerase gamma solely responsible for replication of mitochondrial DNA (mtDNA). Acts as an allosteric regulator of the holoenzyme activities. Enhances the polymerase activity and the processivity of POLG by increasing its interactions with the DNA template. Suppresses POLG exonucleolytic proofreading especially toward homopolymeric templates bearing mismatched termini. Binds to single-stranded DNA.
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.
None
The disease is caused by variants affecting the gene represented in this entry.
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.
None
The disease may be caused by variants affecting the gene represented in this entry.
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.
None
The disease is caused by variants affecting the gene represented in this entry.
Cellular localization
- Mitochondrion
- Mitochondrion matrix
- Mitochondrion nucleoid
Alternative names
MTPOLB, POLG2, DNA polymerase subunit gamma-2, DNA polymerase gamma accessory 55 kDa subunit, Mitochondrial DNA polymerase accessory subunit, MtPolB, PolG-beta, p55