Splicing factor 3B subunit 1, Pre-mRNA-splicing factor SF3b 155 kDa subunit, SF3b155, Spliceosome-associated protein 155, SAP 155, SF3B1, SAP155
Subunit of the splicing factor SF3B 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. May also be involved in the assembly of the E complex. Belongs also to the minor U12-dependent spliceosome, which is involved in the splicing of rare class of nuclear pre-mRNA intron.