. "Recognition of the intron 5'-splice site by components of the assembling spliceosome." . . . "mRNA 5'-splice site recognition" . "nuclear mRNA 5' splice site recognition" . "nuclear mRNA 5'-splice site recognition" . "spliceosomal CC complex biosynthesis" . "spliceosomal CC complex formation" . "spliceosomal commitment complex biosynthesis" . "spliceosomal commitment complex formation" . "spliceosomal E complex biosynthesis" . "spliceosomal E complex formation" . "U12-type nuclear mRNA 5' splice site recognition" . "U12-type nuclear mRNA 5'-splice site recognition" . "U2-type nuclear mRNA 5' splice site recognition" . "U2-type nuclear mRNA 5'-splice site recognition" . . . . . .