The distribution of active force generators controls mitotic spindle position.
During unequal cell divisions a mitotic spindle is eccentrically positioned before cell cleavage. To determine the basis of the net force imbalance that causes spindle displacement in one-cell Caenorhabditis elegans embryos, we fragmented centrosomes with an ultraviolet laser. Analysis of the mean and variance of fragment speeds suggests that the force imbalance is due to a larger number of force generators pulling on astral microtubules of the posterior aster relative to the anterior aster. Moreover, activation of heterotrimeric guanine nucleotide- binding protein (Gprotein) alpha subunits is required to generate these astral forces.
Grill
Stephan W
SW
Max Planck Institute of Molecular Cell Biology and Genetics, D-01307 Dresden, Germany. grill@mpi-cbg.de
Howard
Jonathon
J
Schäffer
Erik
E
Stelzer
Ernst H K
EH
Hyman
Anthony A
AA
D000705:Anaphase; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000648:ultrastructure; D002455:Cell Division; D018385:Centrosome / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000166:cytology; D019084:Fluorescent Antibody Technique, Indirect; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D007834:Lasers; D008433:Mathematics; D008870:Microtubules / Q000502:physiology*; D008938:Mitosis; D008954:Models, Biological; D034622:RNA Interference; D008941:Spindle Apparatus / Q000502:physiology* / Q000648:ultrastructure
D020962:Heterotrimeric GTP-Binding Proteins