Source:http://linkedlifedata.com/resource/umls/id/C1337055
NCI: The 4 major small nuclear ribonucleoprotein particles (snRNPs), U1, U2, U4/U6, and U5, are essential components of the eukaryotic pre-mRNA splicing machinery. These snRNPs share 8 proteins which form the snRNP structural core: SNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE, SNRPF, and SNRPG. These common proteins play an essential role in the biogenesis of the snRNPs. The assembly of the common proteins onto the small nuclear RNA (snRNA) appears to occur in at least 2 steps and involves the formation of RNA-free protein heterooligomers. The common proteins are referred to as Sm proteins because they represent the major targets for the anti-Sm autoantibodies which are diagnostic for SLE. (from OMIM and Swiss-Prot)