A U1-U2 snRNP Interaction Network during Intron Definition

摘要: The assembly of prespliceosomes is responsible for selection intron sites splicing. U1 and U2 snRNPs recognize 5′ splice branch sites, respectively; although there information regarding the composition these complexes, little known about interaction among components or between two snRNPs. Here we describe protein network interactions linking with ATPase Prp5, important site recognition fidelity during first steps reaction, using fission yeast Schizosaccharomyces pombe. snRNP core U1A binds to a novel SR-like protein, Rsd1, which has homologs implicated in transcription. Rsd1 also contacts S. pombe Prp5 (SpPrp5), mediated by domains both proteins. SpPrp5 then through SF3b, conserved DPLD motif Prp5. We show that mutations this have consequences not only vitro (defects prespliceosome formation) but vivo, yielding retention exon skipping defects altered budding Saccharomyces cerevisiae, indicating U1-U2 provides critical, evolutionarily definition.