title: SCF ensures meiotic chromosome segregation through a resolution of meiotic recombination intermediates.
abstract: The SCF (Skp1-Cul1-F-box) complex contributes to a variety of cellular events including meiotic cell cycle control, but its function during meiosis is not understood well. Here we describe a novel function of SCF/Skp1 in meiotic recombination and subsequent chromosome segregation. The skp1 temperature-sensitive mutant exhibited abnormal distribution of spindle microtubules in meiosis II, which turned out to originate from abnormal bending of the spindle in meiosis I. Bent spindles were reported in mitosis of this mutant, but it remained unknown how SCF could affect spindle morphology. We found that the meiotic bent spindle in skp1 cells was due to a hypertension generated by chromosome entanglement. The spindle bending was suppressed by inhibiting double strand break (DSB) formation, indicating that the entanglement was generated by the meiotic recombination machinery. Consistently, Rhp51/Rad51-Rad22/Rad52 foci persisted until meiosis I in skp1 cells, proving accumulation of recombination intermediates. Intriguingly bent spindles were also observed in the mutant of Fbh1, an F-box protein containing the DNA helicase domain, which is involved in meiotic recombination. Genetic evidence suggested its cooperation with SCF/Skp1. Thus, SCF/Skp1 together with Fbh1 is likely to function in the resolution of meiotic recombination intermediates, thereby ensuring proper chromosome segregation.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Hongo, Tokyo, Japan.
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Okamoto
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Toda
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D020090:Chromosome Segregation / Q000235:genetics* / Q000502:physiology; D004265:DNA Helicases / Q000235:genetics / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D005816:Genetic Complementation Test; D008540:Meiosis / Q000235:genetics*; D030781:Organisms, Genetically Modified; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D051721:Rad52 DNA Repair and Recombination Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011995:Recombination, Genetic / Q000235:genetics / Q000502:physiology; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014404:Tubulin / Q000235:genetics / Q000502:physiology
chemical_list: C510980:Atb2 protein, S pombe; D004268:DNA-Binding Proteins; C084232:RHP51 protein, S pombe; D051721:Rad52 DNA Repair and Recombination Protein; D029702:Schizosaccharomyces pombe Proteins; D014404:Tubulin; C085412:rad52 protein, S pombe; D044843:SKP Cullin F-Box Protein Ligases; D051135:Rad51 Recombinase; D004265:DNA Helicases; C504739:Fbh1 protein, S pombe