Disassembly of the nucleus in mitotic extracts: membrane vesicularization, lamin disassembly, and chromosome condensation are independent processes

Cell. 1987 Jan 30;48(2):219-30. doi: 10.1016/0092-8674(87)90425-9.


We describe a stable cell-free mitotic extract derived from Xenopus eggs that contains activities necessary for nuclear envelope breakdown and chromosome condensation during mitosis. Using these cell-free extracts, we have demonstrated that nuclear envelope vesicularization, lamina solubilization, and chromosome condensation are independent and separable biochemical processes. We present evidence indicating that during mitosis nuclear membrane breakdown may involve the binding of a coating protein, lamin solubilization is enzymatically driven, and chromosome condensation involves both binding proteins and enzymatic activities including topoisomerase II. These results provide a coherent framework for investigating structural modification of the nucleus during mitosis at the biochemical level.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Nucleus / metabolism*
  • Cell Nucleus / ultrastructure
  • Cell-Free System
  • Chromosomes / metabolism*
  • Chromosomes / ultrastructure
  • DNA Topoisomerases, Type II / metabolism*
  • Lamins
  • Mitosis*
  • Nuclear Envelope / metabolism*
  • Nuclear Envelope / ultrastructure
  • Nucleoproteins / metabolism*
  • Phosphorylation
  • Solubility
  • Xenopus


  • Lamins
  • Nucleoproteins
  • DNA Topoisomerases, Type II