Splicing factor SPF30 bridges an interaction between the prespliceosome protein U2AF35 and tri-small nuclear ribonucleoprotein protein hPrp3.
Spliceosome assembly is a dynamic process involving the sequential recruitment and rearrangement of small nuclear ribonucleoproteins (snRNPs) on a pre-mRNA substrate. Here we identify several spliceosome protein interactions with different domains of human splicing factor SPF30 that have the potential to mediate the addition of the tri-snRNP to the prespliceosome. In particular, we show that the C-terminal tails of SmD1, SmD3, and the protein Lsm4 interact with the central Tudor domain of SPF30. We identify a novel interaction between the N-terminal domain of SPF30 and U2AF35, a prespliceosome protein that has a role in recognizing the 3' splice site and recruiting U2 snRNP. We also show that the C terminus of SPF30 interacts with a middle domain of hPrp3, a component of U4/U6 di-snRNP and the tri-snRNP. Importantly, we show that the U2AF35 and hPrp3 interactions with SPF30 can occur simultaneously, thereby potentially linking 3' splice site recognition with tri-snRNP addition. Finally, we note that SPF30 and its partner-interacting domains are not conserved in yeast, suggesting this interaction network may play an important role in the complex splicing observed in higher eukaryotes.
Little
John T
JT
Department of Molecular, Cell, and Developmental Biology and Center for Molecular Biology of RNA, University of California, Santa Cruz, CA 95064, USA.
Jurica
Melissa S
MS
D001324:Autoantigens / Q000235:genetics / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000378:metabolism; D055532:SMN Complex Proteins; D017381:Spliceosomes / Q000378:metabolism*; D000072668:Splicing Factor U2AF; D055517:snRNP Core Proteins
D001324:Autoantigens; D017362:Cyclic AMP Response Element-Binding Protein; C485751:LSM4 protein, human; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C108507:PRPF3 protein, human; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D055532:SMN Complex Proteins; C526478:SMNDC1 protein, human; C526409:SNRPD1 protein, human; C526412:SNRPD3 protein, human; D000072668:Splicing Factor U2AF; C076753:U2AF1 protein, human; D055517:snRNP Core Proteins