Reorganization of the microtubule array in prophase/prometaphase requires cytoplasmic dynein-dependent microtubule transport.
When mammalian somatic cells enter mitosis, a fundamental reorganization of the Mt cytoskeleton occurs that is characterized by the loss of the extensive interphase Mt array and the formation of a bipolar mitotic spindle. Microtubules in cells stably expressing GFP-alpha-tubulin were directly observed from prophase to just after nuclear envelope breakdown (NEBD) in early prometaphase. Our results demonstrate a transient stimulation of individual Mt dynamic turnover and the formation and inward motion of microtubule bundles in these cells. Motion of microtubule bundles was inhibited after antibody-mediated inhibition of cytoplasmic dynein/dynactin, but was not inhibited after inhibition of the kinesin-related motor Eg5 or myosin II. In metaphase cells, assembly of small foci of Mts was detected at sites distant from the spindle; these Mts were also moved inward. We propose that cytoplasmic dynein-dependent inward motion of Mts functions to remove Mts from the cytoplasm at prophase and from the peripheral cytoplasm through metaphase. The data demonstrate that dynamic astral Mts search the cytoplasm for other Mts, as well as chromosomes, in mitotic cells.
Rusan
Nasser M
NM
Department of Biology, Program in Molecular and Cellular Biology, Morrill Science Center, University of Massachusetts, N. Pleasant Street, Amherst, MA 01003, USA.
Tulu
U Serdar
US
Fagerstrom
Carey
C
Wadsworth
Patricia
P
D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D000072159:Dynactin Complex; D004398:Dyneins / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016195:G2 Phase / Q000502:physiology; D049452:Green Fluorescent Proteins; D016547:Kinesins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008540:Meiosis; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure*; D024462:Myosin Type II / Q000037:antagonists & inhibitors / Q000378:metabolism; D011418:Prophase; D011743:Pyrimidines / Q000494:pharmacology; D008941:Spindle Apparatus / Q000378:metabolism; D013871:Thiones / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism; D029867:Xenopus Proteins
D000072159:Dynactin Complex; D004791:Enzyme Inhibitors; C088335:KIF11 protein, Xenopus; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D011743:Pyrimidines; D013871:Thiones; D014404:Tubulin; D029867:Xenopus Proteins; D049452:Green Fluorescent Proteins; C400223:monastrol; D024462:Myosin Type II; D004398:Dyneins; D016547:Kinesins