Evidence for a role of Sky1p-mediated phosphorylation in 3' splice site recognition involving both Prp8 and Prp17/Slu4.
The SRPK family of kinases is specific for RS domain-containing splicing factors and known to play a critical role in protein-protein interaction and intracellular distribution of their substrates in both yeast and mammalian cells. However, the function of these kinases in pre-mRNA splicing remains unclear. Here we report that SKY1, a SRPK family member in Saccharomyces cerevisiae, genetically interacts with PRP8 and PRP17/SLU4, both of which are involved in splice site selection during pre-mRNA splicing. Prp8 is essential for splicing and is known to interact with both 5' and 3' splice sites in the spliceosomal catalytic center, whereas Prp17/Slu4 is nonessential and is required only for efficient recognition of the 3' splice site. Interestingly, deletion of SKY1 was synthetically lethal with all prp17 mutants tested, but only with specific prp8 alleles in a domain implicated in governing fidelity of 3'AG recognition. Indeed, deletion of SKY1 specifically suppressed 3'AG mutations in ACT1-CUP1 splicing reporters. These results suggest for the first time that 3' AG recognition may be subject to phosphorylation regulation by Sky1p during pre-mRNA splicing.
Dagher
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SF
Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla 92093-0651, USA.
Fu
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XD
D020413:3' Untranslated Regions; D000483:Alleles; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D005800:Genes, Fungal; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D012322:RNA Precursors; D022821:RNA Splice Sites; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D017415:Ribonucleoprotein, U5 Small Nuclear; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins
D020413:3' Untranslated Regions; C093570:CDC40 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C077018:PRP8 protein, S cerevisiae; D012322:RNA Precursors; D022821:RNA Splice Sites; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D017415:Ribonucleoprotein, U5 Small Nuclear; C093512:SAD1 protein, S pombe; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C490216:SKY1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases