mini spindles: A gene encoding a conserved microtubule-associated protein required for the integrity of the mitotic spindle in Drosophila.
We describe a new Drosophila gene, mini spindles (msps) identified in a cytological screen for mitotic mutant. Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells. Nucleation of microtubules from centrosomes, metaphase alignment of chromosomes, or the focusing of spindle poles appears much less affected. The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast. Consistent with their sequence similarity, Msps protein also associates with microtubules in vitro. In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase. The absence of centrosomal staining in interphase of the cellularized embryos suggests that the interactions between Msps protein and microtubules or centrosomes may be regulated during the cell cycle.
Cullen
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Institute of Cell and Molecular Biology, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom.
Deák
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Glover
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Ohkura
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D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle; D018385:Centrosome / Q000187:drug effects / Q000378:metabolism; D020090:Chromosome Segregation / Q000187:drug effects; D003001:Cloning, Molecular; D003078:Colchicine / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D005260:Female; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D017239:Paclitaxel / Q000494:pharmacology; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins
C486738:CKAP5 protein, Xenopus; C454180:CKAP5 protein, human; D019476:Insect Proteins; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins; D029867:Xenopus Proteins; C094879:dis1 protein, S pombe; D017239:Paclitaxel; D003078:Colchicine