title: Conserved Wat1/Pop3 WD-repeat protein of fission yeast secures genome stability through microtubule integrity and may be involved in mRNA maturation.
abstract: Accurate chromosome segregation is dependent upon the integrity of mitotic spindles, which pull each pair of sister chromatids towards opposite poles. In this study, we have characterised fission yeast pop3-5235, a diploidising mutant that is impaired in genome stability. Pop3 is the same as Wat1, a conserved protein containing 7 WD repeats. Pop3/Wat1 has also been isolated from a two-hybrid screen as a binding partner to Prp2, the large subunit of the essential splicing factor U2AF. In wat1 mutants, the cellular amount of alpha-tubulin is decreased to very low levels, which results in compromised microtubules and spindles, consequently leading to unequal chromosome separation. Further analysis shows that, in spite of the binding between Wat1 and Prp2, Wat1 may not be involved directly in splicing reactions per se. Instead, we find that Wat1 is required for the maintenance of alpha-tubulin mRNA levels; moreover, transcript levels of genes other than the alpha-tubulin gene are also equally decreased in this mutant. Wild-type Wat1, but not the mutant protein, forms a large complex in the cell with several other proteins, suggesting that Wat1 functions as a structural linker in the complex. The results suggest that Wat1 plays a role in mRNA maturation as a coupling protein between splicing and synthesis and/or stabilisation.
authors.affiliation: Laboratory of Cell Regulation, Imperial Cancer Research Fund, London, UK.
authors.forename: I L
authors.initials: IL
authors.lastname: Ochotorena
authors.forename: D
authors.initials: D
authors.lastname: Hirata
authors.forename: K
authors.initials: K
authors.lastname: Kominami
authors.forename: J
authors.initials: J
authors.lastname: Potashkin
authors.forename: F
authors.initials: F
authors.lastname: Sahin
authors.forename: K
authors.initials: K
authors.lastname: Wentz-Hunter
authors.forename: K L
authors.initials: KL
authors.lastname: Gould
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: L
authors.initials: L
authors.lastname: Vardy
authors.forename: T
authors.initials: T
authors.lastname: Toda
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D053487:DEAD-box RNA Helicases; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D016681:Genome, Fungal; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins; D010641:Phenotype; D011485:Protein Binding; D012326:RNA Splicing; D020871:RNA Stability; D012331:RNA, Fungal / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000166:cytology* / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000072668:Splicing Factor U2AF; D014158:Transcription, Genetic / Q000235:genetics; D014404:Tubulin / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D005656:Fungal Proteins; D009687:Nuclear Proteins; C105525:Pop3 protein, S pombe; D012331:RNA, Fungal; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D000072668:Splicing Factor U2AF; D014404:Tubulin; C000607494:U2AF2 protein, human; C066490:PRP2 protein, S cerevisiae; D053487:DEAD-box RNA Helicases