title: Aurora kinase inhibitor ZM447439 blocks chromosome-induced spindle assembly, the completion of chromosome condensation, and the establishment of the spindle integrity checkpoint in Xenopus egg extracts.
abstract: The Aurora family kinases contribute to accurate progression through several mitotic events. ZM447439 ("ZM"), the first Aurora family kinase inhibitor to be developed and characterized, was previously found to interfere with the mitotic spindle integrity checkpoint and chromosome segregation. Here, we have used extracts of Xenopus eggs, which normally proceed through the early embryonic cell cycles in the absence of functional checkpoints, to distinguish between ZM's effects on the basic cell cycle machinery and its effects on checkpoints. ZM clearly had no effect on either the kinetics or amplitude in the oscillations of activity of several key cell cycle regulators. It did, however, have striking effects on chromosome morphology. In the presence of ZM, chromosome condensation began on schedule but then failed to progress properly; instead, the chromosomes underwent premature decondensation during mid-mitosis. ZM strongly interfered with mitotic spindle assembly by inhibiting the formation of microtubules that are nucleated/stabilized by chromatin. By contrast, ZM had little effect on the assembly of microtubules by centrosomes at the spindle poles. Finally, under conditions where the spindle integrity checkpoint was experimentally induced, ZM blocked the establishment, but not the maintenance, of the checkpoint, at a point upstream of the checkpoint protein Mad2. These results show that Aurora kinase activity is required to ensure the maintenance of condensed chromosomes, the generation of chromosome-induced spindle microtubules, and activation of the spindle integrity checkpoint.
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Bedrick B
authors.initials: BB
authors.lastname: Gadea
authors.forename: Joan V
authors.initials: JV
authors.lastname: Ruderman
mesh_terms: D000818:Animals; D064127:Aurora Kinases; D001549:Benzamides / Q000494:pharmacology*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D002875:Chromosomes / Q000648:ultrastructure; D019926:Cyclin B / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006657:Histones / Q000737:chemistry; D015151:Immunoblotting; D007700:Kinetics; D020935:MAP Kinase Signaling System; D064246:Mad2 Proteins; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008928:Mitochondria / Q000378:metabolism; D008938:Mitosis; D009865:Oocytes / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017231:Proto-Oncogene Proteins c-mos / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology*; D012097:Repressor Proteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D013997:Time Factors; D014982:Xenopus laevis; D020931:ran GTP-Binding Protein / Q000737:chemistry; D020666:ras-GRF1 / Q000378:metabolism
chemical_list: C474722:4-(4-(N-benzoylamino)anilino)-6-methoxy-7-(3-(1-morpholino)propoxy)quinazoline; D001549:Benzamides; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D019926:Cyclin B; D004791:Enzyme Inhibitors; D006657:Histones; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; D011799:Quinazolines; D012097:Repressor Proteins; D020666:ras-GRF1; D011494:Protein Kinases; C102333:histone H1 kinase; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D017231:Proto-Oncogene Proteins c-mos; D016203:CDC2 Protein Kinase; D020931:ran GTP-Binding Protein