Self-organization of microtubules into bipolar spindles around artificial chromosomes in Xenopus egg extracts

Nature. 1996 Aug 1;382(6590):420-5. doi: 10.1038/382420a0.


Functional nuclei and mitotic spindles are shown to assemble around DNA-coated beads incubated in Xenopus egg extracts. Bipolar spindles assemble in the absence of centrosomes and kinetochores, indicating that bipolarity is an intrinsic property of microtubules assembling around chromatin in a mitotic cytoplasm. Microtubules nucleated at dispersed sites with random polarity rearrange into two arrays of uniform polarity. Spindle-pole formation requires cytoplasmic dynein-dependent translocation of microtubules across one another. It is proposed that spindles form in the absence of centrosomes by motor-dependent sorting of microtubules according to their polarity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Extracts
  • Chromatin / physiology
  • Chromatin / ultrastructure
  • Chromosomes / physiology*
  • Drosophila / genetics
  • Dyneins / physiology
  • Male
  • Microspheres
  • Microtubules / physiology*
  • Mitosis / physiology
  • Ovum / physiology
  • Plasmids
  • Spermatozoa / physiology
  • Spindle Apparatus / physiology*
  • Xenopus


  • Cell Extracts
  • Chromatin
  • Dyneins