POLG2: DNA Polymerase Gamma 2, Accessory Subunit
Essential regulator of mitochondrial DNA replication and maintenance
Gene Information Card
| Symbol | POLG2 |
|---|---|
| Full Name | DNA polymerase gamma 2, accessory subunit |
| Gene Type | Protein coding |
| Chromosomal Location | 17q23.3 |
| NCBI Gene ID | 11232 ncbi.nlm.nih.gov/gene/11232 |
| Ensembl ID | ENSG00000156531 |
| UniProt ID | Q9UHN1 |
| OMIM ID | 604983 |
| HGNC ID | 9180 |
| Aliases | HP55, MTPOLB, POLB, POLG2P1 |
Description
POLG2 encodes the 55 kDa accessory subunit of mitochondrial DNA polymerase gamma (Pol γ). This subunit enhances the processivity and DNA binding affinity of the catalytic subunit (POLG1), and is essential for accurate and efficient replication of mitochondrial DNA (mtDNA). Mutations in POLG2 are associated with autosomal dominant progressive external ophthalmoplegia (adPEO) and other mitochondrial disorders.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Progressive external ophthalmoplegia, autosomal dominant 4 | Impaired mtDNA replication due to reduced processivity of Pol γ | ClinVar, OMIM |
| Mitochondrial DNA depletion syndrome | Defective mtDNA maintenance leading to tissue-specific depletion | ClinVar |
| Mitochondrial recessive ataxia syndrome | Disrupted mtDNA replication in neural tissues | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 12.5 | Medium |
| Skeletal muscle | 10.8 | Medium |
| Liver | 8.3 | Medium |
| Brain | 7.1 | Low |
| Kidney | 6.9 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 15.2 | Cervical cancer cell line |
| HepG2 | 12.8 | Hepatocellular carcinoma |
| K562 | 9.5 | Leukemia cell line |
| A549 | 8.1 | Lung carcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1369C>T (p.Arg457Trp) | Missense | Rare | Reduced processivity; associated with adPEO |
| c.1399G>A (p.Glu467Lys) | Missense | Rare | Impaired interaction with POLG1; adPEO |
| c.848T>C (p.Leu283Pro) | Missense | Very rare | Decreased DNA binding; mitochondrial disease |
Mutation functional classification
Loss of Function (LOF)
Missense mutations (e.g., p.Arg457Trp) reduce processivity and DNA binding, impairing mtDNA replication.
Gain of Function (GOF)
No known gain-of-function mutations reported.
Dominant Negative (DN)
Mutations such as p.Glu467Lys exert dominant-negative effects by disrupting the POLG1-POLG2 complex.
View complete mutation data：
Gene Ontology (GO)
| • DNA-directed DNA polymerase activity (GO:0003887) | • mitochondrion (GO:0005739) |
| • DNA replication (GO:0006260) | • mitochondrial nucleoid (GO:0042645) |
| • mitochondrial DNA replication (GO:1902990) |
Pathways
• Mitochondrial DNA replication (Reactome: R-HSA-1592230)
• Mitochondrial genome maintenance (KEGG: hsa04932)
Protein Summary
POLG2 encodes the 55 kDa accessory subunit of mitochondrial DNA polymerase gamma. This protein forms a heterotrimeric complex with the catalytic subunit (POLG1) to enable high-fidelity replication of the mitochondrial genome. It enhances processivity by increasing the affinity of the polymerase for DNA and is critical for mtDNA maintenance. Defects in POLG2 lead to mitochondrial disorders such as progressive external ophthalmoplegia.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| POLG2 Knockout HEK293 Cell Line | EDJ-KQ7339 | Human | 11232 | Details Get a Quote |
| POLG2 Knockout HCT 116 Cell Line | EDJ-KQ32436 | Human | 11232 | Details Get a Quote |
| POLG2 Knockout HeLa Cell Line | EDJ-KQ32437 | Human | 11232 | Details Get a Quote |
| POLG2 Knockout A-549 Cell Line | EDJ-KQ64107 | Human | 11232 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
