Term Name:	cis assembly of pre-catalytic spliceosome
Synonyms:	cis assembly of U12-type pre-catalytic spliceosome, cis assembly of U2-type pre-catalytic spliceosome, formation of spliceosomal A2-1 complex, formation of spliceosomal B1 complex, spliceosomal A2-1 complex biosynthesis, spliceosomal A2-1 complex formation, spliceosomal B1 complex biosynthesis, spliceosomal B1 complex formation
Definition:	Assembly of a spliceosomal complex containing the intact pre-mRNA and all of the spliceosomal snRNPs. This occurs when the tri-snRNP associates with the pre-mRNA and associated snRNPs in an ATP-dependent manner.
Ontology:	GO: Biological Process [GO:0000354]    QuickGO    AmiGO