U6 snRNP

GO:0005688 · Ribonucleoprotein · Ribonucleoprotein complex · Proposed

A ribonucleoprotein complex that contains small nuclear RNA U6, the Lsm2-8 heptameric ring complex, as well as several proteins that are unique to the U6 snRNP, most of which remain associated with the U6 snRNA both while the U6 snRNP is free or assembled into the U4/U6 snRNP or into a series of spliceosomal complexes. [GO:0005688]

Synonyms: snRNP U6

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
U6 snRNA	Rna	part of	`SO:0000396`				U6 small nuclear RNA constituent named in the U6 snRNP definition and grounded to the U6 snRNA Sequence Ontology term. `GO:0005688` GO:0005688 defines the U6 snRNP as containing small nuclear RNA U6. `SO:0000396` SO:0000396 is the Sequence Ontology term for U6 snRNA.
Lsm2-8 complex	Protein complex	part of	`GO:0120115`				Lsm2-8 heptameric ring complex constituent named in the U6 snRNP definition. `GO:0005688` GO:0005688 defines the U6 snRNP as containing the Lsm2-8 heptameric ring complex. `GO:0120115` GO:0120115 defines the Lsm2-8 complex as the heteroheptameric complex composed of Lsm2, Lsm3, Lsm4, Lsm5, Lsm6, Lsm7 and Lsm8 or their orthologs.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: The U6 snRNP subcomplex is represented in budding-yeast U4/U6.U5 tri-snRNP cryo-EM structures; broader eukaryotic distribution is left for follow-up curation. [DOI:10.1038/nature16940]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model whose U6 snRNP subcomplex is represented inside U4/U6.U5 tri-snRNP cryo-EM structures. [DOI:10.1038/nature16940]

Mechanism graphs

U6 snRNA and the Lsm2-8 complex are U6 snRNP constituents (ASSEMBLY)

The U6 snRNP contains U6 small nuclear RNA and the GO-grounded Lsm2-8 heptameric ring complex; GO:0005688 also states that additional U6-specific proteins are present, with exact family boundaries still to be resolved.

Subject	Predicate	Object	Evidence
U6 snRNA	contributes constituents to	U6 snRNP	`GO:0005688` GO:0005688 defines the U6 snRNP as containing small nuclear RNA U6.
Lsm2-8 complex	contributes constituents to	U6 snRNP	`GO:0005688` GO:0005688 defines the U6 snRNP as containing the Lsm2-8 heptameric ring complex. `GO:0120115` GO:0120115 is the Gene Ontology cellular-component term for the Lsm2-8 complex.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings for individual Lsm proteins and U6-specific protein families that form the U6 snRNP. The first GO:0005688 record captures U6 snRNA and the GO-defined Lsm2-8 complex at coarse granularity. Individual Lsm proteins and U6-specific protein-family boundaries should be resolved before splitting this inventory.

Evidence

GO:0005688 Gene Ontology cellular-component term for the U6 snRNP and its exact synonym.
GO:0097525 Gene Ontology cellular-component parent term for spliceosomal snRNP complex.
SO:0000396 Sequence Ontology term for U6 snRNA.
GO:0120115 Gene Ontology cellular-component term for the Lsm2-8 complex.
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.

Curation history

2026-09-24T16:19:14Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-24T16:19:47Z codex · EXPANDED_RECORD — Added the GO exact synonym, spliceosomal snRNP parentage, U6 snRNA and Lsm2-8-ring components, budding-yeast distribution, Nguyen/Galej/Nagai yeast U4/U6.U5 tri-snRNP cryo-EM evidence, a minimal U6 snRNP constituent graph and a protein-component grounding TODO.
2026-09-24T16:32:25Z codex · ADDRESS_REVIEW — #1507: replaced the label-only Lsm2-8-ring component with the GO:0120115-grounded Lsm2-8 complex and propagated that grounding to the constituent graph.

Source: data/structures/ribonucleoprotein/u6_snrnp.yaml