title: Removal of a single alpha-tubulin gene intron suppresses cell cycle arrest phenotypes of splicing factor mutations in Saccharomyces cerevisiae.
abstract: Genetic and biochemical studies of Schizosaccharomyces pombe and Saccharomyces cerevisiae have identified gene products that play essential functions in both pre-mRNA splicing and cell cycle control. Among these are the conserved, Myb-related CDC5 (also known as Cef1p in S. cerevisiae) proteins. The mechanism by which loss of CDC5/Cef1p function causes both splicing and cell cycle defects has been unclear. Here we provide evidence that cell cycle arrest in a new temperature-sensitive CEF1 mutant, cef1-13, is an indirect consequence of defects in pre-mRNA splicing. Although cef1-13 cells harbor global defects in pre-mRNA splicing discovered through intron microarray analysis, inefficient splicing of the alpha-tubulin-encoding TUB1 mRNA was considered as a potential cause of the cef1-13 cell cycle arrest because cef1-13 cells arrest uniformly at G(2)/M with many hallmarks of a defective microtubule cytoskeleton. Consistent with this possibility, cef1-13 cells possess reduced levels of total TUB1 mRNA and alpha-tubulin protein. Removing the intron from TUB1 in cef1-13 cells boosts TUB1 mRNA and alpha-tubulin expression to near wild-type levels and restores microtubule stability in the cef1-13 mutant. As a result, cef1-13 tub1Deltai cells progress through mitosis and their cell cycle arrest phenotype is alleviated. Removing the TUB1 intron from two other splicing mutants that arrest at G(2)/M, prp17Delta and prp22-1 strains, permits nuclear division, but suppression of the cell cycle block is less efficient. Our data raise the possibility that although cell cycle arrest phenotypes in prp mutants can be explained by defects in pre-mRNA splicing, the transcript(s) whose inefficient splicing contributes to cell cycle arrest is likely to be prp mutant dependent.
authors.affiliation: Howard Hughes Medical Institute, Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors.forename: C Geoffrey
authors.initials: CG
authors.lastname: Burns
authors.forename: Ryoma
authors.initials: R
authors.lastname: Ohi
authors.forename: Sapna
authors.initials: S
authors.lastname: Mehta
authors.forename: Eileen T
authors.initials: ET
authors.lastname: O'Toole
authors.forename: Mark
authors.initials: M
authors.lastname: Winey
authors.forename: Tyson A
authors.initials: TA
authors.lastname: Clark
authors.forename: Charles W
authors.initials: CW
authors.lastname: Sugnet
authors.forename: Manuel
authors.initials: M
authors.lastname: Ares
authors.forename: Kathleen L
authors.initials: KL
authors.lastname: Gould
mesh_terms: D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics*; D053487:DEAD-box RNA Helicases; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D007438:Introns; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases; D020365:RNA Helicases; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D000072260:RNA Splicing Factors; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins; D013696:Temperature; D014404:Tubulin / Q000235:genetics*
chemical_list: C093570:CDC40 protein, S cerevisiae; C513239:CEF1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D012322:RNA Precursors; D000072260:RNA Splicing Factors; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014404:Tubulin; C085875:cdc5 protein, S pombe; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C081927:CDC5 protein, S cerevisiae; C067135:PRP22 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases