DnaA-HU complex

GO:1990103 · Other · Nucleoprotein complex · Proposed

A protein-DNA complex containing DNA-bound DnaA attached to HU. HU is a dimer encoded by two closely related genes. Essential for the initiation of replication in bacteria; stimulates the DnaA-dependent unwinding of oriC. [GO:1990103]

Synonyms: DnaA-HU-DNA complex

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
DnaA replication initiation protein	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	dnaA		UNKNOWN	DNA-bound initiator constituent contacted by HU in the oriC-bound complex. `GO:1990103` GO:1990103 defines the DnaA-HU complex as containing DNA-bound DnaA attached to HU. `PMID:18179598` Chodavarapu et al. 2008 studied E. coli DnaA interaction with HU during initiation at the E. coli replication origin.
HU histone-like protein dimer	Protein complex	part of	Reviewed label only (reviewed name; no accession asserted)		dimer	UNKNOWN	Dimeric histone-like protein constituent attached to DNA-bound DnaA in the DnaA-HU complex. `GO:1990103` GO:1990103 defines the DnaA-HU complex as containing HU and notes that HU is a dimer encoded by two closely related genes. `PMID:18179598` Chodavarapu et al. 2008 studied HU interaction with E. coli DnaA during initiation at the replication origin.
oriC origin DNA	Dna	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Origin DNA scaffold for the DNA-bound DnaA/HU nucleoprotein complex. `GO:1990103` GO:1990103 defines this entity as a protein-DNA complex and scopes HU stimulation to DnaA-dependent unwinding of oriC. `PMID:18179598` Chodavarapu et al. 2008 studied initiation at the E. coli replication origin.

Taxonomic distribution

NCBITaxon:562 Escherichia coli — COMMON: Chodavarapu et al. 2008 studied E. coli DnaA interaction with HU during initiation at the E. coli replication origin. [PMID:18179598]

Canonical examples

NCBITaxon:562 Escherichia coli — Chodavarapu et al. 2008 examined DnaA-HU interaction in initiation at the E. coli replication origin. [PMID:18179598]

Functions

DNA replication initiation GO:0006270 — The DnaA-HU complex participates in bacterial DNA replication initiation by stimulating DnaA-dependent oriC unwinding.
- GO:1990103 GO:1990103 defines the DnaA-HU complex as essential for replication initiation in bacteria and as stimulating DnaA-dependent unwinding of oriC.
- GO:0006270 GO:0006270 is the Gene Ontology biological-process term for DNA replication initiation.
- PMID:18179598 Chodavarapu et al. 2008 studied E. coli DnaA and HU during initiation at the E. coli replication origin.

Mechanism graphs

HU stimulates DnaA-dependent oriC unwinding (FUNCTION)

HU attaches to DNA-bound DnaA on oriC to form a nucleoprotein complex that supports DNA replication initiation.

Subject	Predicate	Object	Evidence
DnaA replication initiation protein	contributes to	DnaA-HU complex	`GO:1990103` GO:1990103 defines the complex as containing DNA-bound DnaA attached to HU.
HU histone-like protein dimer	contributes to	DnaA-HU complex	`GO:1990103` GO:1990103 names HU as part of this DnaA-containing complex.
oriC origin DNA	scaffolds	DnaA-HU complex	`GO:1990103` GO:1990103 defines the complex as a protein-DNA complex and scopes it to DnaA-dependent oriC unwinding. `PMID:18179598` Chodavarapu et al. 2008 studied the E. coli replication origin.
DnaA-HU complex	supports	DNA replication initiation	`GO:1990103` GO:1990103 defines the DnaA-HU complex as essential for bacterial replication initiation. `GO:0006270` GO:0006270 is the DNA replication initiation process term.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral DnaA, HU and oriC origin DNA groundings for the DnaA-HU complex. GO:1990103 defines the DnaA-HU complex around DNA-bound DnaA, a HU dimer and oriC DNA. Exact source-neutral InterPro, Pfam, NCBIfam, UniProt family or SO sequence-feature CURIEs for these components need narrower curation before the labels can be grounded.
INTERPRETATION (RESOLVED): Keep the GO:1990103 HU-containing complex distinct from DnaA-oriC, DnaA-DiaA and DnaB-DnaC helicase loading. GO:1990103 denotes a HU-containing DnaA-DNA complex. GO models the plain DnaA-oriC complex as GO:1990101, the DiaA-containing complex as GO:1990102, and DnaB-DnaC helicase loading separately as GO:1990100.

Evidence

GO:1990103 Gene Ontology cellular-component term for the DnaA-HU complex and its exact DnaA-HU-DNA complex synonym.
GO:1990077 QuickGO reports GO:1990103 as an is-a child of GO:1990077 primosome complex.
GO:1990101 Gene Ontology cellular-component term for the separately scoped DnaA-oriC complex.
GO:1990102 Gene Ontology cellular-component term for the separately scoped DnaA-DiaA complex.
GO:1990100 Gene Ontology cellular-component term for the separate DnaB-DnaC helicase-loading complex.
GO:0006270 Gene Ontology biological-process term for DNA replication initiation.
PMID:18179598 PubMed identifier for Chodavarapu et al. 2008, the Molecular Microbiology paper cited by GO:1990103.
DOI:10.1111/j.1365-2958.2007.06094.x DOI for Chodavarapu et al. 2008, 'Escherichia coli DnaA interacts with HU in initiation at the E. coli replication origin', as reported by PubMed.

Curation history

2026-10-01T10:51:37Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-01T10:52:47Z codex · EXPANDED_RECORD — Added GO synonymy, primosome-complex parentage, reviewed-label-only DnaA, HU and oriC DNA components, E. coli DnaA-HU initiation evidence, DNA-replication-initiation function evidence, GO/PubMed/DOI evidence, a nonmechanistic DnaA-HU graph, and grounding/boundary discussions.
2026-10-01T11:08:12Z codex · FIX_REVIEW_ISSUE — Addressed PR #1867 review issue #1868 by removing unsupported DNA-bending mechanism text from the nonmechanistic DnaA-HU graph scope.

Source: data/structures/other/dnaa_hu_complex.yaml