nuclear mRNA branch site recognition, U12-type nuclear mRNA branch site recognition, U2-type nuclear mRNA branch site recognition, spliceosomal A complex biosynthesis, spliceosomal A complex formation, spliceosomal B complex biosynthesis, spliceosomal B complex formation
Alternate IDs
GO:0000370, GO:0000371
Definition
Recognition of the pre-mRNA branch site sequence by components of the assembling spliceosome.
Source:
GOC:krc,
ISBN:0879695897
Comment
Note that this step represents the formation of the B complex (yeast) or the A complex (mammalian).