title: Centrosome separation and central spindle assembly act in redundant pathways that regulate microtubule density and trigger cleavage furrow formation.
abstract: The mitotic spindle provides the spatial cue that coordinates cytokinesis with nuclear division. However, the specific property of the mitotic spindle that mediates this spatial regulation remains obscure, in part because different aspects of the mitotic spindle appear to have furrow inducing activity in different systems. We show that in C. elegans embryos, although the central spindle is usually dispensable for furrow initiation, it becomes essential for furrow formation when the extent of centrosome separation during anaphase is reduced. Measurements of microtubule density demonstrate that furrow formation occurs in the vicinity of a local minimum of microtubule density. Reduction of the extent of spindle elongation or disruption of the central spindle causes delayed formation of the cleavage furrow. These data suggest that reduced microtubule density triggers cleavage furrow initiation and demonstrate that redundant mechanisms direct efficient formation of the cleavage furrow.
authors.affiliation: Research Institute of Molecular Pathology (IMP), Dr Bohr-Gasse 7, A-1030, Vienna, Austria.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dechant
authors.forename: Michael
authors.initials: M
authors.lastname: Glotzer
mesh_terms: D000818:Animals; D064096:Aurora Kinase A; D064127:Aurora Kinases; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000502:physiology*; D018385:Centrosome / Q000378:metabolism* / Q000648:ultrastructure; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D016547:Kinesins / Q000172:deficiency / Q000235:genetics; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C114455:ZEN-4 protein, C elegans; C087977:par-2 protein, C elegans; D064096:Aurora Kinase A; D064127:Aurora Kinases; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases; C576939:air-1 protein, C elegans; D016547:Kinesins; D020742:rhoA GTP-Binding Protein