Protein functions in pre-mRNA splicing

Proteins have been implicated in an expanding variety of functions during pre-mRNA splicing. Molecular cloning has identified genes encoding spliceosomal proteins that potentially act as novel RNA helicases, GTPases, or protein isomerases. Novel protein—protein and protein—RNA interactions that are required for functional spliceosome formation have also been described. Finally, growing evidence suggests that proteins may contribute directly to the spliceosome's active sites.