commitment complex

GO:0000243 · Ribonucleoprotein · Ribonucleoprotein complex · Proposed

A spliceosomal complex that is formed by association of the U1 snRNP with the 5' splice site of an unspliced intron in an RNA transcript. [GO:0000243]

Synonyms: mammalian spliceosomal complex E; mammalian spliceosomal E complex; yeast spliceosomal complex CC

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
U1 snRNP	Protein complex	part of	`GO:0005685`				Small nuclear ribonucleoprotein associated with the 5-prime splice site of the unspliced intron in the commitment complex. `GO:0000243` GO:0000243 defines the commitment complex by association of U1 snRNP with the 5-prime splice site. `GO:0005685` GO:0005685 is the Gene Ontology cellular-component term for the U1 snRNP.

Mechanism graphs

U1 snRNP association forms the commitment complex (ASSEMBLY)

The commitment complex forms when U1 snRNP associates with the 5-prime splice site of an unspliced intron in an RNA transcript.

Subject	Predicate	Object	Evidence
U1 snRNP	associates with 5-prime splice site in	commitment complex	`GO:0000243` GO:0000243 defines the commitment complex by U1 snRNP association with the 5-prime splice site of an unspliced intron.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral component boundaries for commitment complex proteins beyond the GO-defined U1 snRNP subcomplex, and decide how to represent the bound unspliced-intron RNA. The first GO:0000243 record captures the defining U1 snRNP subcomplex. Additional commitment-complex proteins and the splice-site substrate RNA should be resolved into exact source-neutral families, subcomplexes or RNAs before expanding this component list.

Evidence

GO:0000243 Gene Ontology cellular-component term for the commitment complex and its GO synonyms.
GO:0005684 Gene Ontology cellular-component parent term for U2-type spliceosomal complex.
GO:0005685 Gene Ontology cellular-component term for the U1 snRNP.
GO:0071004 Gene Ontology cellular-component term for the U2-type prespliceosome, a subsequent U2-type spliceosome state.
DOI:10.1016/s0092-8674(00)80221-4 Abovich and Rosbash 1997, Cross-intron bridging interactions in the yeast commitment complex are conserved in mammals, Cell.
PMID:9150140 PubMed identifier for Abovich and Rosbash 1997 as reported by NCBI E-utilities.

Curation history

2026-09-25T02:28:55Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-25T02:29:39Z codex · EXPANDED_RECORD — Added GO narrow synonyms, U2-type parentage, the GO-grounded U1 snRNP component, Abovich/Rosbash commitment-complex evidence, a conservative U1 splice-site association graph and a protein/RNA component grounding TODO.

Source: data/structures/ribonucleoprotein/commitment_complex.yaml