Assembly and dynamics of an anastral:astral spindle: the meiosis II spindle of Drosophila oocytes.
The meiosis II spindle of Drosophila oocytes is distinctive in structure, consisting of two tandem spindles with anastral distal poles and an aster-associated spindle pole body between the central poles. Assembly of the anastral:astral meiosis II spindle occurs by reorganization of the meiosis I spindle, without breakdown of the meiosis I spindle. The unusual disk- or ring-shaped central spindle pole body forms de novo in the center of the elongated meiosis I spindle, followed by formation of the central spindle poles. gamma-Tubulin transiently localizes to the central spindle pole body, implying that the body acts as a microtubule nucleating center for assembly of the central poles. Localization of gamma-tubulin to the meiosis II spindle is dependent on the microtubule motor protein, Nonclaret disjunctional (Ncd). Absence of Ncd results in loss of gamma-tubulin localization to the spindle and destabilization of microtubules in the central region of the spindle. Assembly of the anastral:astral meiosis II spindle probably involves rapid reassortment of microtubule plus and minus ends in the center of the meiosis I spindle - this can be accounted for by a model that also accounts for the loss of gamma-tubulin localization to the spindle and destabilization of microtubules in the absence of Ncd.
Department of Microbiology, Duke University Medical Center, Durham, NC 27710, USA. endow@galactose.mc.duke.edu
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D000251:Adenosine Triphosphatases; D000818:Animals; D004330:Drosophila / Q000166:cytology* / Q000196:embryology; D029721:Drosophila Proteins; D005816:Genetic Complementation Test; D007150:Immunohistochemistry; D016547:Kinesins / Q000235:genetics; D008540:Meiosis / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D009154:Mutation; D009865:Oocytes / Q000166:cytology; D010063:Ovum / Q000166:cytology; D008941:Spindle Apparatus / Q000378:metabolism* / Q000502:physiology*; D014404:Tubulin / Q000032:analysis* / Q000235:genetics / Q000378:metabolism
D029721:Drosophila Proteins; D014404:Tubulin; C066696:ncd protein, Drosophila; D000251:Adenosine Triphosphatases; D016547:Kinesins