MeSH note : mediates specific interactions between U1 & U2 small nuclear ribonucleoprotein particles
at the 3'-splice site; necessary for the splicing of pre-mRNA; required for formation
of the earliest ATP-dependent splicing complex and interacts with spliceosomal components
bound to both the 5' and 3' splice sites during spliceosome assembly; RefSeq NM_011358;