Spindle formation and chromatin condensation in cells blocked at interphase by mutation of a negative cell cycle control gene

Cell. 1988 Jan 29;52(2):241-51. doi: 10.1016/0092-8674(88)90513-2.


In Aspergillus nidulans the temperature-sensitive cell cycle mutation bimE7 causes chromosome condensation and pre-anaphase spindle formation to occur at restrictive temperature. By constructing double mutants between bimE7 and S phase or G2 phase mutants and blocking DNA replication with hydroxyurea, we demonstrate that bimE7 can cause chromatin condensation and spindle formation in cells held in S or G2. Thus bimE7 overrides normal control systems that prevent mitosis from prematurely occurring during S or G2. We show that bimE7 is a loss of function mutation and propose that bimE normally functions to negatively control a positive mitotic inducing factor, possibly the cell cycle gene nimA.

Publication types

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

MeSH terms

  • Aspergillus nidulans / genetics*
  • Aspergillus nidulans / ultrastructure
  • Cell Cycle*
  • Chromatin / ultrastructure*
  • DNA / genetics
  • DNA Replication / drug effects
  • DNA, Recombinant
  • Fluorescent Antibody Technique
  • Genes, Fungal*
  • Hydroxyurea / pharmacology
  • Interphase*
  • Microtubules / ultrastructure
  • Mitotic Index
  • Mutation
  • Plasmids
  • Spindle Apparatus / ultrastructure*
  • Temperature
  • Transformation, Genetic
  • Tubulin / analysis


  • Chromatin
  • DNA, Recombinant
  • Tubulin
  • DNA
  • Hydroxyurea