title: Cell Size Determines the Strength of the Spindle Assembly Checkpoint during Embryonic Development.
abstract: The spindle assembly checkpoint (SAC) delays mitotic progression when chromosomes are not properly attached to microtubules of the mitotic spindle. Cells vary widely in the extent to which they delay mitotic progression upon SAC activation. To explore the mechanisms that determine checkpoint strength in different cells, we systematically measured the mitotic delay induced by microtubule disruption at different stages of embryogenesis in Caenorhabditis elegans. Strikingly, we observed a gradual increase in SAC strength after each round of division. Analysis of mutants that alter cell size or ploidy revealed that SAC strength is determined primarily by cell size and the number of kinetochores. These findings provide clear evidence in vivo that the kinetochore-to-cytoplasm ratio determines the strength of the SAC, providing new insights into why cells exhibit such large variations in their SAC responses.
authors: Department of Physiology and Department of Biochemistry and Biophysics, University of California, 600 16(th) Street, San Francisco, CA 94143, USA. Electronic address: m.galli@hubrecht.eu.
authors: Matilde
authors: M
authors: Galli
authors: Department of Physiology and Department of Biochemistry and Biophysics, University of California, 600 16(th) Street, San Francisco, CA 94143, USA. Electronic address: david.morgan@ucsf.edu.
authors: David O
authors: DO
authors: Morgan
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics; D018797:Cell Cycle Proteins / Q000378:metabolism; D048429:Cell Size; D020090:Chromosome Segregation / Q000502:physiology; D018386:Kinetochores / Q000378:metabolism*; D059566:M Phase Cell Cycle Checkpoints / Q000235:genetics*; D008870:Microtubules / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins