Small ribonucleoprotein particle U1 subunit 70K (snRNP-U1-70K) encodes a protein component of the U1 snRNP. The U1 snRNP combines with other snRNPs on the pre-mRNA to assemble a spliceosome.

Splicing factor 3b subunit 1, isoform A; RNA binding; mRNA binding. It is involved in the biological process described with: spliceosomal complex assembly; mRNA splicing, via spliceosome.

Probable small nuclear ribonucleoprotein G; Plays role in pre-mRNA splicing as core component of the SMN- Sm complex that mediates spliceosomal snRNP assembly. Plays role in pre-mRNA splicing as component of the spliceosomal U1, U2, U4 and U5 small nuclear ribonucleoproteins (snRNPs), the building blocks of the spliceosome. Component of both the pre-catalytic spliceosome B complex and activated spliceosome C complexes. Is also a component of the minor U12 spliceosome (By similarity).

Splicing factor 1, isoform A; Zinc ion binding; pre-mRNA branch point binding; RNA binding; mRNA binding. It is involved in the biological process described with: regulation of alternative mRNA splicing, via spliceosome; mRNA splicing, via spliceosome.

Splicing factor 3B subunit 3; Involved in pre-mRNA splicing as a component of the splicing factor SF3B complex, a constituent of the spliceosome. SF3B complex is required for 'A' complex assembly formed by the stable binding of U2 snRNP to the branchpoint sequence (BPS) in pre-mRNA. Sequence independent binding of SF3A/SF3B complex upstream of the branch site is essential, it may anchor U2 snRNP to the pre-mRNA (By similarity). May also be involved in the assembly of the 'E' complex (By similarity). Belongs also to the minor U12-dependent spliceosome, which is involved in the splicing [...]

Splicing factor 2 (SF2) encodes a protein involved in alternative mRNA splicing, RNA export from the nucleus and the regulation of the RNA metabolism.

Small ribonucleoprotein particle protein SmF (SmF) encodes an RNA binding protein that functions as part of a heteroheptameric ring structure called the Sm core. This complex binds to spliceosomal small nuclear RNAs (e.g. U1, U2, U4 and U5) and helps to carry out pre-mRNA splicing. It also forms a heterotrimeric sub-complex with the products of SmE and SNRPG.

Small ribonucleoprotein particle protein SmD2 (SmD2) encodes an RNA binding protein that forms a heterodimeric sub-complex with the product of SmD1. They function as part of the heteroheptameric ring complex Sm core, which is involved in the formation of spliceosomal small nuclear RNPs (U1, U2, U4 and U5), which together catalyze pre-mRNA splicing.

Probable U2 small nuclear ribonucleoprotein A; Involved in pre-mRNA splicing as component of the spliceosome (By similarity). Associated with sn-RNP U2, where it contributes to the binding of stem loop IV of U2 snRNA (By similarity). In the germ line, has a role in oogenesis, by regulating spermatogenesis and nurse cell nuclei chromatin decondensation and dispersal, probably by regulating the splicing of proteins necessary for germline differentiation such as the meiotic protein mei-P26. Belongs to the U2 small nuclear ribonucleoprotein A family.