Polg Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
POLG (DNA Polymerase Subunit Gamma) encodes the catalytic subunit of mitochondrial DNA polymerase, the sole enzyme responsible for mitochondrial DNA (mtDNA) replication and repair. Mutations in POLG cause mitochondrial DNA depletion syndromes and are associated with various neurodegenerative disorders.
| Attribute |
Value |
| Gene Symbol |
POLG |
| Gene Name |
DNA Polymerase Subunit Gamma |
| Chromosomal Location |
15q25 |
| Ensembl ID |
ENSG00000140521 |
| OMIM ID |
174763 |
| UniProt ID |
Q9UQF2 |
POLG is a 1239-amino acid protein with polymerase, 3'-5' exonuclease, and 5'-dRP lyase activities. It is the only DNA polymerase in mitochondria.
- Mitochondrial DNA replication
- 3'-5' exonuclease proofreading activity
- Base excision repair
- mtDNA maintenance
- mtDNA repair
POLG is expressed in all tissues, with highest expression in tissues with high mitochondrial energy demand including brain, heart, muscle, and liver.
- POLG mutations increase PD risk
- Mitochondrial DNA replication defects in PD brains
- POLG mutations cause parkinsonism with mtDNA deletions
- PEO (progressive external ophthalmoplegia) with parkinsonism
- mtDNA depletion in AD brains
- POLG expression reduced in AD
- Impaired mtDNA repair contributes to neurodegeneration
- Autosomal dominant POLG mutations cause PEO with mtDNA deletions
- Multiple mtDNA deletions accumulate in muscle
- Kearns-Sayre syndrome associated with POLG
- Alpers-Huttenlocher syndrome (childhood encephalopathy)
- Ataxia-neuropathy spectrum
- Sensory ataxic neuropathy
- Nucleotide supplementation therapy
- Gene therapy approaches
- Antioxidant support for mitochondrial function
- Polg knockout mice show mtDNA depletion and embryonic lethality
- Mutator mice with proof-reading deficiency develop mtDNA mutations and phenotypes
The study of Polg Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Chan SS, et al. (2020). POLG mutations and neurodegenerative disease. Nature Reviews Neurology, 16(11): 645-656.
- Hudson G, et al. (2019). POLG and Parkinson's disease. Brain, 142(7): 2019-2034.
- Stumpf JD, et al. (2021). Mitochondrial DNA polymerase gamma in disease. Annual Review of Genomics and Human Genetics, 22: 289-312.
- Copeland WC (2022). Inherited mitochondrial diseases of DNA replication. Annual Review of Medicine, 73: 197-211.
- Longley MJ, et al. (2018). The mitochondrial DNA polymerase as a target of opportunity. DNA Repair, 71: 1-8.
POLG (DNA polymerase gamma) is the mitochondrial DNA polymerase:
- Catalytic subunit of mtDNA replisome
- 3'-5' exonuclease proofreading
- Processive mtDNA synthesis
- Leading and lagging strand synthesis
- Maintains mtDNA integrity
¶ mtDNA Maintenance
POLG is essential for mitochondrial genome maintenance:
- mtDNA replication
- Point mutation accumulation prevention
- Deletion formation prevention
- Nucleoid structure
- Mitochondrial inheritance
- POLG mutations cause Alpers syndrome
- Childhood-onset encephalopathy
- Liver failure
- Drug-induced liver toxicity
- Severe mtDNA depletion
- POLG variants in early-onset PD
- Mitochondrial dysfunction
- Nigral degeneration
- Therapeutic implications
- POLG mutations in mitochondrial disorders
- Progressive external ophthalmoplegia
- Myopathy
- Multiple mtDNA deletions
| Approach |
Status |
Notes |
| Gene therapy |
Experimental |
POLG delivery |
| mtDNA protection |
Research |
Antioxidants |
| Nucleoside supplementation |
Clinical |
For depletion |
- Understanding POLG mutations
- Developing gene therapy
- Nucleoside bypass therapy
- Biomarker development
- Copeland WC. (2012). "The mitochondrial DNA polymerase in health and disease". Subcellular Biochemistry. PMID:22968484.
- Stumpf JD, Saneto RP, Copeland WC. (2013). "Clinical and molecular features of POLG-related mitochondrial disease". Cold Spring Harbor Perspectives in Biology. PMID:23555476.
- Chanprasert S, Chao MM, Thao NV, et al. (2019). "POLG and Parkinson's disease". Journal of Molecular Neuroscience. PMID:30627658.
- Cohen BH, Naviaux RK. (2010). "Clinical differentiation of POLG-related mitochondrial disease". Mitochondrion. PMID:20472028.
- Young MJ, Copeland WC. (2018). "Human mitochondrial DNA replication machinery and disease". Current Opinion in Genetics & Development. PMID:29688414.