FACT complex

GO:0035101 · Other · Multiprotein complex · Proposed

A histone chaperone complex that facilitates nucleosome disassembly and reassembly upon DNA or RNA polymerase passage. [GO:0035101]

Synonyms: Facilitates chromatin transcription 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
Spt16 FACT subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SPT16		UNKNOWN	Large histone-chaperone constituent of the budding-yeast Spt16-Pob3 FACT core. `DOI:10.1093/emboj/20.13.3506` Formosa et al. 2001 reported that the Saccharomyces cerevisiae Spt16/Cdc68 and Pob3 proteins form the yeast Spt16-Pob3 heterodimer.
Pob3 FACT subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	POB3		UNKNOWN	Protein constituent of the budding-yeast Spt16-Pob3 FACT core that supplies the SSRP1-related middle domain. `DOI:10.1093/emboj/20.13.3506` Formosa et al. 2001 reported that the Saccharomyces cerevisiae Spt16/Cdc68 and Pob3 proteins form the yeast Spt16-Pob3 heterodimer.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast is the organism in which Formosa et al. 2001 characterized the Spt16-Pob3 heterodimer that combines with Nhp6 to form the nucleosome-binding factor SPN. [DOI:10.1093/emboj/20.13.3506]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Formosa et al. 2001 used budding-yeast genetics and protein interaction assays to show that Spt16/Cdc68 and Pob3 form a heterodimeric chromatin factor. [DOI:10.1093/emboj/20.13.3506]

Functions

nucleosome organization GO:0034728 — FACT reorganizes nucleosomes by facilitating disassembly and reassembly during polymerase passage.
- GO:0035101 GO:0035101 defines the FACT complex as facilitating nucleosome disassembly and reassembly upon polymerase passage.
- GO:0034728 GO:0034728 is the Gene Ontology biological-process term for nucleosome organization.
- DOI:10.1126/science.1085703 Belotserkovskaya et al. 2003 assayed FACT-dependent nucleosome alteration and intrinsic histone chaperone activity.
DNA-templated transcription elongation GO:0006354 — FACT helps RNA polymerase II elongate transcripts through nucleosomal DNA templates.
- GO:0006354 GO:0006354 is the Gene Ontology biological-process term for DNA-templated transcription elongation.
- DOI:10.1126/science.1085703 Belotserkovskaya et al. 2003 studied FACT activity in RNA polymerase II transcription through nucleosomes.

Mechanism graphs

FACT supports nucleosome reorganization during transcription (FUNCTION)

In Saccharomyces cerevisiae, the Spt16-Pob3 FACT core works with Nhp6 to reorganize nucleosomes and supports RNA polymerase II transcription through nucleosomal templates.

Subject	Predicate	Object	Evidence
Spt16 FACT subunit	contributes to	FACT complex	`DOI:10.1093/emboj/20.13.3506` Formosa et al. 2001 reported that Spt16/Cdc68 and Pob3 form a heterodimer in budding yeast.
Pob3 FACT subunit	contributes to	FACT complex	`DOI:10.1093/emboj/20.13.3506` Formosa et al. 2001 reported that Spt16/Cdc68 and Pob3 form a heterodimer in budding yeast.
FACT complex	supports	nucleosome organization	`GO:0035101` GO:0035101 defines FACT as a histone chaperone complex that facilitates nucleosome disassembly and reassembly during polymerase passage.
FACT complex	supports	DNA-templated transcription elongation	`DOI:10.1126/science.1085703` Belotserkovskaya et al. 2003 studied FACT-dependent RNA polymerase II transcription through nucleosomes.

Discussions

CURATION_TODO (RESOLVED): Do not model Nhp6 as a core FACT complex constituent. Formosa et al. 2001 reported that Spt16/Cdc68 and Pob3 form a yeast heterodimer and that this heterodimer combines with Nhp6 to form the nucleosome-binding factor SPN, supporting Nhp6 as a DNA-binding cofactor for the yeast SPN activity rather than one of the two FACT core constituents.
CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for the FACT complex constituents. The curated FACT component labels are yeast gene-name-based classes. This pass verified the gene symbols and the Spt16-Pob3 composition but did not verify exact InterPro, Pfam, NCBIfam or UniProt family CURIEs that should be reused across fungi.

Evidence

GO:0035101 Gene Ontology cellular-component term for FACT complex and its Facilitates chromatin transcription complex exact synonym.
GO:0008023 Gene Ontology cellular-component parent term for transcription elongation factor complexes.
GO:0034728 Gene Ontology biological-process term for nucleosome organization.
GO:0006354 Gene Ontology biological-process term for DNA-templated transcription elongation.
PMID:12934006 PubMed identifier for Belotserkovskaya et al. 2003, the FACT nucleosome-alteration paper cited by GO:0035101.
DOI:10.1126/science.1085703 DOI for Belotserkovskaya et al. 2003, 'FACT facilitates transcription-dependent nucleosome alteration', verified through NCBI E-utilities.
PMID:11432837 PubMed identifier for Formosa et al. 2001, the budding-yeast Spt16-Pob3 and Nhp6 SPN paper.
DOI:10.1093/emboj/20.13.3506 DOI for Formosa et al. 2001, 'Spt16-Pob3 and the HMG protein Nhp6 combine to form the nucleosome-binding factor SPN', verified through NCBI E-utilities.

Curation history

2026-09-26T06:31:20Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-26T06:32:31Z codex · EXPANDED_RECORD — Added FACT exact synonymy, transcription-elongation-factor-complex parentage, two budding-yeast FACT constituent rows, yeast scope, nucleosome organization and transcription elongation functions, GO/PubMed/DOI evidence, a nonmechanistic function graph, a resolved Nhp6 boundary discussion, and a FACT subunit-grounding TODO.

Source: data/structures/other/fact_complex.yaml