The distribution of active force generators controls mitotic spindle position

Science. 2003 Jul 25;301(5632):518-21. doi: 10.1126/science.1086560.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaphase
  • Animals
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / ultrastructure
  • Cell Division*
  • Centrosome / physiology
  • Embryo, Nonmammalian / cytology
  • Fluorescent Antibody Technique, Indirect
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Lasers
  • Mathematics
  • Microtubules / physiology*
  • Mitosis
  • Models, Biological
  • RNA Interference
  • Spindle Apparatus / physiology*
  • Spindle Apparatus / ultrastructure


  • Heterotrimeric GTP-Binding Proteins