title: The roles of fission yeast ase1 in mitotic cell division, meiotic nuclear oscillation, and cytokinesis checkpoint signaling.
abstract: The Ase1/Prc1 proteins constitute a conserved microtubule-associated protein family that is implicated in central spindle formation and cytokinesis. Here we characterize a role for fission yeast Ase1. Ase1 localizes to microtubule overlapping zones and displays dynamic alterations of localization during the cell cycle. In particular, its spindle localization during metaphase is reduced substantially, followed by robust appearance at the spindle midzone in anaphase. ase1 deletions are viable but defective in nuclear and septum positioning and completion of cytokinesis, which leads to diploidization and chromosome loss. Time-lapse imaging shows that elongating spindles collapse abruptly in the middle of anaphase B. Either absence or overproduction of Ase1 results in profound defects on microtubule bundling in an opposed manner, indicating that Ase1 is a dose-dependent microtubule-bundling factor. In contrast microtubule nucleating activities are not noticeably compromised in ase1 mutants. During meiosis astral microtubules are not bundled and oscillatory nuclear movement is impaired significantly. The Aurora kinase does not correctly localize to central spindles in the absence of Ase1. Finally Ase1 acts as a regulatory component in the cytokinesis checkpoint that operates to inhibit nuclear division when the cytokinesis apparatus is perturbed. Ase1, therefore, couples anaphase completion with cytokinesis upon cell division.
authors.affiliation: Molecular Genetics Research Laboratory, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamashita
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Sato
authors.forename: Akiko
authors.initials: A
authors.lastname: Fujita
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Toda
mesh_terms: D000205:Actomyosin / Q000737:chemistry; D000705:Anaphase; D064127:Aurora Kinases; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism*; D002470:Cell Survival; D048749:Cytokinesis; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019084:Fluorescent Antibody Technique, Indirect; D016678:Genome; D005838:Genotype; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007399:Interphase; D018386:Kinetochores / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008540:Meiosis; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D008957:Models, Genetic; D009154:Mutation; D009991:Oscillometry; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D012568:Schizosaccharomyces / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000502:physiology*; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000378:metabolism; D013997:Time Factors; D000097573:Red Fluorescent Protein
chemical_list: D000205:Actomyosin; D064127:Aurora Kinases; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D000097573:Red Fluorescent Protein; C472767:Ase1 protein, S cerevisiae; C502827:Ase1 protein, S pombe