Ribonucleoprotein, U1 Small Nuclear

**Definition:** A nuclear RNA-protein complex that plays a role in RNA processing. In the nucleoplasm, the U1 snRNP along with other small nuclear ribonucleoproteins (U2, U4-U6, and U5) assemble into SPLICEOSOMES that remove introns from pre-mRNA by splicing. The U1 snRNA forms base pairs with conserved sequence motifs at the 5'-splice site and recognizes both the 5'- and 3'-splice sites and may have a fundamental role in aligning the two sites for the splicing reaction.

**Tree numbers:** - D12.776.157.725.500.875.600 - D12.776.157.725.829.313 - D12.776.664.962.500.875.600 - D12.776.664.962.829.313

**Synonyms:** - Small Nuclear Ribonucleoproteins, U1 - U1 Small Nuclear Ribonucleoproteins - U1 snRNP - Ribonucleoproteins, Small, U1