U4/U6 x U5 tri-snRNP complex

GO:0046540 · Ribonucleoprotein · Ribonucleoprotein complex · Proposed

A ribonucleoprotein complex that is formed by the association of the U4/U6 and U5 snRNPs. [GO:0046540]

Synonyms: U4/U6.U5 snRNP complex; U4/U6.U5 tri-snRNP

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
U4/U6 snRNP	Protein complex	part of	`GO:0071001`				Base-paired U4/U6 small nuclear ribonucleoprotein subcomplex that associates with U5 snRNP to form the U4/U6 x U5 tri-snRNP complex. `GO:0046540` GO:0046540 defines the U4/U6 x U5 tri-snRNP complex as formed by association of the U4/U6 and U5 snRNPs. `GO:0071001` GO:0071001 is the Gene Ontology cellular-component term for the U4/U6 snRNP.
U5 snRNP	Protein complex	part of	`GO:0005682`				U5 small nuclear ribonucleoprotein subcomplex that associates with U4/U6 snRNP in the spliceosomal tri-snRNP. `GO:0046540` GO:0046540 defines the U4/U6 x U5 tri-snRNP complex as formed by association of the U4/U6 and U5 snRNPs. `GO:0005682` GO:0005682 is the Gene Ontology cellular-component term for the U5 snRNP.

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: The U4/U6.U5 tri-snRNP is directly evidenced in budding yeast by cryo-electron microscopy; broader eukaryotic distribution is left for follow-up curation. [DOI:10.1038/nature16940]

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast U4/U6.U5 tri-snRNP whose architecture and high-resolution cryo-EM structure were reported by Nguyen, Galej, Bai and colleagues. [DOI:10.1038/nature16940]

The spliceosomal U4/U6 x U5 tri-snRNP complex forms when the U4/U6 snRNP associates with the U5 snRNP.

Subject	Predicate	Object	Evidence
U4/U6 snRNP	contributes to assembly of	U4/U6 x U5 tri-snRNP complex	`GO:0046540` GO:0046540 defines the complex as the product of U4/U6 snRNP and U5 snRNP association.
U5 snRNP	contributes to assembly of	U4/U6 x U5 tri-snRNP complex	`GO:0046540` GO:0046540 defines the complex as the product of U4/U6 snRNP and U5 snRNP association.

CURATION_TODO (OPEN): Resolve exact source-neutral groundings for individual U4/U6.U5 tri-snRNP protein families observed in yeast, including Prp8, Brr2, Snu114, Prp6, Prp3, Prp4, Prp31 and Snu66/Sad1-family factors. The first GO:0046540 record captures the GO-grounded U4/U6 and U5 snRNP subcomplexes that define the tri-snRNP. Individual protein family boundaries, source-neutral groundings and cross-eukaryotic orthology should be resolved before splitting the protein inventory.

GO:0046540 Gene Ontology cellular-component term for the U4/U6 x U5 tri-snRNP complex and its exact synonym.
GO:0097526 Gene Ontology cellular-component parent term for spliceosomal tri-snRNP complex.
GO:0071001 Gene Ontology cellular-component term for the U4/U6 snRNP.
GO:0005682 Gene Ontology cellular-component term for the U5 snRNP.
DOI:10.1038/nature14548 Nguyen, Galej, Bai and colleagues 2015, The architecture of the spliceosomal U4/U6.U5 tri-snRNP, Nature.
PMID:26106855 PubMed identifier for Nguyen, Galej, Bai and colleagues 2015 as reported by PubMed.
DOI:10.1038/nature16940 Nguyen, Galej, Bai and colleagues 2016, Cryo-EM structure of the yeast U4/U6.U5 tri-snRNP at 3.7 Angstrom resolution, Nature.
PMID:26829225 PubMed identifier for Nguyen, Galej, Bai and colleagues 2016 as reported by PubMed.

2026-09-24T13:20:08Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-24T13:21:23Z codex · EXPANDED_RECORD — Added the GO exact synonym, spliceosomal tri-snRNP parentage, GO-grounded U4/U6 and U5 snRNP components, budding-yeast distribution, Nguyen/Galej/Nagai yeast cryo-EM evidence, an assembly graph and a protein-component grounding TODO.
2026-09-24T13:34:36Z codex · ADDRESS_REVIEW — #1492: added the DOI-backed U4/U6.U5 tri-snRNP literature synonym; #1493: reworded the assembly graph scope note so it no longer makes a cryo-EM-specific claim backed only by GO edge evidence.