gamma DNA polymerase complex

GO:0005760 · Other · Multiprotein complex · Proposed

A DNA polymerase complex consisting of a large subunit, responsible for the catalytic activities, and a small accessory subunit. Functions in the replication and repair of mitochondrial DNA. [GO:0005760]

Part of: mitochondrial matrix (GO:0005759)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
DNA polymerase gamma catalytic subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	POLG		UNKNOWN	Catalytic DNA polymerase gamma constituent that carries the polymerase and exonuclease activities of the mitochondrial DNA polymerase. `GO:0005760` GO:0005760 defines the gamma DNA polymerase complex as a large catalytic subunit and a small accessory subunit that function in mitochondrial DNA replication and repair. `PMID:10608893` Lim et al. reconstituted human Hp140 with the p55 accessory subunit as an active DNA polymerase gamma complex.
DNA polymerase gamma accessory subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	POLG2		UNKNOWN	Accessory DNA polymerase gamma constituent that stimulates processive mitochondrial DNA synthesis by the catalytic subunit. `GO:0005760` GO:0005760 defines the gamma DNA polymerase complex as a large catalytic subunit and a small accessory subunit that function in mitochondrial DNA replication and repair. `PMID:10608893` Lim et al. showed that human p55 forms a stable complex with the p140 catalytic subunit and enhances DNA binding and processive DNA synthesis. `PMID:11172710` Carrodeguas et al. showed that mammalian Pol gamma B, the accessory subunit of DNA polymerase gamma, functions as a homodimer.

Taxonomic distribution

NCBITaxon:2759 Eukaryota — COMMON: GO:0005760 defines the gamma DNA polymerase complex and constrains the cellular-component term to Eukaryota. [GO:0005760]

Canonical examples

NCBITaxon:9606 Homo sapiens — Reference mammalian system in which the p55 accessory subunit was cloned and reconstituted with the p140 DNA polymerase gamma catalytic subunit. [PMID:10608893]

Functions

mitochondrial DNA replication GO:0006264 — The gamma DNA polymerase complex supports synthesis of new mitochondrial DNA strands.
- GO:0005760 GO:0005760 defines the gamma DNA polymerase complex as functioning in mitochondrial DNA replication.
- GO:0006264 GO:0006264 is the Gene Ontology biological-process term for mitochondrial DNA replication.
- PMID:10608893 Lim et al. connected the human catalytic and p55 accessory subunits to DNA polymerase gamma forms that act in mitochondrial DNA repair and replication.

Mechanism graphs

DNA polymerase gamma supports mitochondrial DNA replication (FUNCTION)

The DNA polymerase gamma catalytic and accessory subunits form a mitochondrial polymerase complex that supports mitochondrial DNA replication.

Subject	Predicate	Object	Evidence
DNA polymerase gamma catalytic subunit	contributes to	gamma DNA polymerase complex	`GO:0005760` GO:0005760 defines the gamma DNA polymerase complex as a large catalytic subunit and a small accessory subunit that function in mitochondrial DNA replication and repair. `PMID:10608893` Lim et al. reconstituted human Hp140 with the p55 accessory subunit as an active DNA polymerase gamma complex.
DNA polymerase gamma accessory subunit	contributes to	gamma DNA polymerase complex	`GO:0005760` GO:0005760 defines the gamma DNA polymerase complex as a large catalytic subunit and a small accessory subunit that function in mitochondrial DNA replication and repair. `PMID:10608893` Lim et al. showed that human p55 forms a stable complex with the p140 catalytic subunit. `PMID:11172710` Carrodeguas et al. showed that mammalian Pol gamma B, the accessory subunit of DNA polymerase gamma, functions as a homodimer.
gamma DNA polymerase complex	supports	mitochondrial DNA replication	`GO:0005760` GO:0005760 defines the complex as functioning in mitochondrial DNA replication. `GO:0006264` GO:0006264 defines mitochondrial DNA replication.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for the DNA polymerase gamma catalytic and accessory subunit classes. GO:0005760 exactly identifies the gamma DNA polymerase complex and primary human and mammalian evidence directly supports the catalytic and accessory subunit classes, but exact source-neutral InterPro, Pfam, NCBIfam or UniProtKB family CURIEs were not curated in this pass.
INTERPRETATION (RESOLVED): Represent the homodimeric mammalian Pol gamma B accessory subunit as a single accessory-subunit class. GO:0005760 names a large catalytic subunit and a small accessory subunit; mammalian structural evidence shows that the accessory subunit functions as a homodimer. The component list models molecular classes, so the accessory subunit remains a single component class rather than two duplicate component rows.

Evidence

GO:0005760 Gene Ontology cellular-component term for the gamma DNA polymerase complex.
GO:0042575 Gene Ontology cellular-component parent term for DNA polymerase complexes.
GO:0098798 Gene Ontology cellular-component parent term for mitochondrial protein-containing complexes.
GO:0005759 Gene Ontology cellular-component term for the mitochondrial matrix; GO:0005760 is part of this term.
GO:0006264 Gene Ontology biological-process term for mitochondrial DNA replication.
PMID:12045093 PubMed record for Hubscher et al. 2002, the eukaryotic DNA polymerases review cited by GO:0005760.
PMID:10608893 PubMed record for Lim et al. 1999, the JBC paper that cloned the human p55 DNA polymerase gamma accessory subunit and reconstituted it with the p140 catalytic subunit.
PMID:11172710 PubMed record for Carrodeguas et al. 2001, the Molecular Cell paper showing that mammalian Pol gamma B functions as a homodimer.

Curation history

2026-09-27T20:30:48Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-27T20:31:40Z codex · EXPANDED_RECORD — Added DNA-polymerase-complex and mitochondrial-protein-complex parentage, mitochondrial-matrix parthood, two reviewed-label-only human Pol gamma constituent rows, Eukaryota scope and a human canonical example, mitochondrial-DNA-replication function evidence, GO/PubMed evidence, a nonmechanistic function graph, a subunit-grounding TODO, and a resolved discussion for modeling the homodimeric accessory subunit as one component class.

Source: data/structures/other/gamma_dna_polymerase_complex.yaml