alpha DNA polymerase:primase complex

GO:0005658 · Other · Multiprotein complex · Proposed

A complex of four polypeptides, comprising large and small DNA polymerase alpha subunits and two primase subunits, which are capable of catalyzing the synthesis of an RNA primer on the lagging strand of replicating DNA and the subsequent synthesis of a small stretch of DNA. [GO:0005658]

Synonyms: DNA polymerase alpha:primase complex; heterotetrameric polymerase alpha holoenzyme; pol-prim

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

Components

Component	Type	Part of / acts on	Grounding	Essential	Role
DNA polymerase alpha large subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Large DNA polymerase alpha constituent class of the four-subunit complex. `GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
DNA polymerase alpha small subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Small DNA polymerase alpha constituent class of the four-subunit complex. `GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
DNA primase large subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Large DNA primase constituent class of the four-subunit complex. `GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
DNA primase small subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Catalytic small DNA primase constituent class of the four-subunit complex. `GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits. `PMID:11395402` The PubMed abstract for the DNA primase review states that the small eukaryotic primase subunit contains the active site for RNA synthesis.

Taxonomic distribution

NCBITaxon:2759 Eukaryota — COMMON: GO:0005658 defines an alpha DNA polymerase:primase complex and constrains the cellular-component term to Eukaryota. [GO:0005658]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — The four budding-yeast DNA polymerase alpha-primase subunits are assembled throughout the cell cycle. [PMID:8621497]

Functions

DNA replication, synthesis of primer GO:0006269 — The alpha DNA polymerase:primase complex synthesizes an RNA primer on lagging-strand templates and then synthesizes a short stretch of DNA.
- GO:0005658 GO:0005658 defines the complex by RNA-primer synthesis on lagging-strand DNA and subsequent short DNA synthesis.
- GO:0006269 GO:0006269 is the Gene Ontology biological-process term for DNA replication primer synthesis.
- PMID:26975377 The PubMed abstract for the 2016 human primosome structural paper describes coordinated RNA-DNA primer synthesis by primase and DNA polymerase alpha.

Mechanism graphs

DNA polymerase alpha-primase synthesizes primers (FUNCTION)

The large and small DNA polymerase alpha subunits plus the two DNA primase subunits form a four-subunit complex that synthesizes RNA-DNA primers.

Subject	Predicate	Object	Evidence
DNA polymerase alpha large subunit	contributes to	alpha DNA polymerase:primase complex	`GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
DNA polymerase alpha small subunit	contributes to	alpha DNA polymerase:primase complex	`GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
DNA primase large subunit	contributes to	alpha DNA polymerase:primase complex	`GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
DNA primase small subunit	contributes to	alpha DNA polymerase:primase complex	`GO:0005658` GO:0005658 defines the alpha DNA polymerase:primase complex as a four-polypeptide complex comprising large and small DNA polymerase alpha subunits plus two primase subunits.
alpha DNA polymerase:primase complex	supports	DNA replication, synthesis of primer	`GO:0005658` GO:0005658 defines the complex by RNA-primer synthesis and subsequent short DNA synthesis. `GO:0006269` GO:0006269 defines DNA replication primer synthesis.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for the alpha DNA polymerase and primase subunit classes. GO:0005658 exactly identifies the four-polypeptide alpha DNA polymerase:primase complex and names large and small DNA polymerase alpha subunits plus two primase subunits, but exact source-neutral InterPro, Pfam, NCBIfam or UniProtKB family CURIEs were not curated in this pass.

Evidence

GO:0005658 Gene Ontology cellular-component term for the alpha DNA polymerase:primase complex.
GO:0042575 Gene Ontology cellular-component parent term for DNA polymerase complexes.
GO:0006269 Gene Ontology biological-process term for DNA replication primer synthesis.
PMID:11395402 PubMed record for the DNA primases review cited by GO:0005658.
PMID:26975377 PubMed record for the human primosome structural paper cited by GO:0005658.
PMID:8621497 PubMed record for a Saccharomyces cerevisiae DNA polymerase alpha-primase B-subunit paper reporting four-subunit assembly.

Curation history

2026-09-27T18:10:42Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-27T18:12:03Z codex · EXPANDED_RECORD — Added GO synonymy and parentage, four reviewed-label-only constituent classes, Eukaryota scope, a Saccharomyces cerevisiae canonical example, DNA-replication-primer-synthesis function evidence, GO/PubMed evidence, a nonmechanistic function graph, and a subunit-grounding TODO.
2026-09-27T18:12:53Z codex · NORMALIZED_YAML — De-aliased repeated GO:0005658 evidence entries so the YAML emits without anchors.

Source: data/structures/other/alpha_dna_polymerase_primase_complex.yaml