U4atac/U6atac snRNP

GO:0071002 · Ribonucleoprotein · Ribonucleoprotein complex · Proposed

A ribonucleoprotein complex that contains the extensively base paired small nuclear RNAs U4atac and U6atac, a heptameric ring of Sm proteins associated with U4atac, the Lsm2-8 heptameric ring complex associated with U6atac, as well as several proteins that are unique to the U4atac snRNP or U6atac snRNPs, some of which remain associated with the U4atac/U6atac snRNA both while the U4atac snRNP is free or assembled into a series of spliceosomal complexes. [GO:0071002]

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
U4atac snRNP	Protein complex	part of	`GO:0005690`				U4atac small nuclear ribonucleoprotein subcomplex that contributes U4atac snRNA, a Sm protein ring and U4atac-associated proteins to the U4atac/U6atac snRNP. `GO:0071002` GO:0071002 defines the U4atac/U6atac snRNP as containing small nuclear RNA U4atac, a U4atac-associated heptameric Sm ring and U4atac- or U6atac-specific proteins. `GO:0005690` GO:0005690 is the Gene Ontology cellular-component term for the U4atac snRNP.
U6atac snRNP	Protein complex	part of	`GO:0005691`				U6atac small nuclear ribonucleoprotein subcomplex that contributes U6atac snRNA, the Lsm2-8 ring and U6atac-associated proteins to the U4atac/U6atac snRNP. `GO:0071002` GO:0071002 defines the U4atac/U6atac snRNP as containing small nuclear RNA U6atac, a U6atac-associated Lsm2-8 heptameric ring and U4atac- or U6atac-specific proteins. `GO:0005691` GO:0005691 is the Gene Ontology cellular-component term for the U6atac snRNP.

Taxonomic distribution

NCBITaxon:9606 Homo sapiens — COMMON: The U4atac/U6atac snRNP subcomplex is represented in human U4atac/U6atac.U5 tri-snRNPs analyzed biochemically by Schneider, Will, Makarova and colleagues; broader eukaryotic distribution is left for follow-up curation. [DOI:10.1128/MCB.22.10.3219-3229.2002]

Canonical examples

NCBITaxon:9606 Homo sapiens — Human minor-spliceosome U4atac/U6atac snRNP represented inside U4atac/U6atac.U5 tri-snRNPs in the Schneider, Will and Makarova comparative composition study. [DOI:10.1128/MCB.22.10.3219-3229.2002]

Mechanism graphs

U4atac and U6atac snRNP constituents define the U4atac/U6atac snRNP (ASSEMBLY)

The U4atac/U6atac snRNP contains extensively base-paired U4atac and U6atac small nuclear RNAs together with the U4atac-associated Sm ring, the U6atac-associated Lsm2-8 ring and U4atac/U6atac-associated proteins.

Subject	Predicate	Object	Evidence
U4atac snRNP	contributes constituents to	U4atac/U6atac snRNP	`GO:0071002` GO:0071002 defines the U4atac/U6atac snRNP as containing small nuclear RNA U4atac and a heptameric ring of Sm proteins associated with U4atac.
U6atac snRNP	contributes constituents to	U4atac/U6atac snRNP	`GO:0071002` GO:0071002 defines the U4atac/U6atac snRNP as containing small nuclear RNA U6atac and the Lsm2-8 heptameric ring associated with U6atac.

Discussions

CURATION_TODO (OPEN): Review whether the Sm ring and GO:0120115 Lsm2-8 complex should be promoted as direct nested components, and resolve exact source-neutral groundings for individual U4atac/U6atac-specific protein families. The first GO:0071002 record captures the U4atac and U6atac snRNP subcomplexes at GO-grounded granularity. GO:0120115 already grounds the Lsm2-8 complex, so follow-up curation should decide whether the Sm and Lsm2-8 rings belong as direct nested components here and should resolve U4atac/U6atac-specific protein-family boundaries before splitting the protein inventory.

Evidence

GO:0071002 Gene Ontology cellular-component term for the U4atac/U6atac snRNP.
GO:0097525 Gene Ontology cellular-component parent term for spliceosomal snRNP complex.
GO:0005690 Gene Ontology cellular-component term for the U4atac snRNP.
GO:0005691 Gene Ontology cellular-component term for the U6atac snRNP.
DOI:10.1128/MCB.22.10.3219-3229.2002 Schneider, Will, Makarova and colleagues 2002, Human U4/U6.U5 and U4atac/U6atac.U5 tri-snRNPs exhibit similar protein compositions, Molecular and Cellular Biology.
PMID:11971955 PubMed identifier for Schneider, Will, Makarova and colleagues 2002 as reported by NCBI E-utilities.
DOI:10.1515/BC.2005.084 Will and Luehrmann 2005, Splicing of a rare class of introns by the U12-dependent spliceosome, Biological Chemistry.
PMID:16201866 PubMed identifier for Will and Luehrmann 2005 as reported by NCBI E-utilities.

Curation history

2026-09-24T20:06:05Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-24T20:07:07Z codex · EXPANDED_RECORD — Added spliceosomal snRNP parentage, GO-grounded U4atac and U6atac snRNP components, human Schneider/Will/Makarova tri-snRNP evidence, a minimal U4atac/U6atac constituent graph and a protein-component grounding TODO.
2026-09-24T20:16:50Z codex · ADDRESS_REVIEW — #1521: narrowed the U4atac/U6atac protein-component TODO so it no longer frames the already GO:0120115-grounded Lsm2-8 complex as ungrounded.

Source: data/structures/ribonucleoprotein/u4atac_u6atac_snrnp.yaml