Premature chromatin condensation upon accumulation of NIMA

Matthew J. O'Connell, Chris Norbury, Paul Nurse

Research output: Contribution to journalArticlepeer-review

103 Scopus citations


The NIMA protein kinase of Aspergillus nidulans is required for the G2/M transition of the cell cycle. Mutants lacking NIMA arrest without morphological characteristics of mitosis, but they do contain an activated p37(nimX) kinase (the Aspergillus homologue of p34(cdc2)). To gain a better understanding of NIMA function we have investigated the effects of expressing various NIMA constructs in Aspergillus, fission yeast and human cells. Our experiments have shown that the instability of the NIMA protein requires sequences in the non-catalytic C-terminus of the protein. Removal of this domain results in a stable protein that, once accumulated, promotes a lethal premature condensation of chromatin without any other aspects of mitosis. Similar effects were also observed in fission yeast and human cells accumulating Aspergillus NIMA. This phenotype is independent of cell cycle progression and does not require p34(cdC2) kinase activity. As gain of NIMA function by accumulation results in premature chromatin condensation, and loss of NIMA function results in an inability to enter mitosis, we propose that NIMA functions in G2 to promote the condensation of chromatin normally associated with entry into mitosis.

Original languageEnglish
Pages (from-to)4926-4937
Number of pages12
JournalEMBO Journal
Issue number20
StatePublished - 1994
Externally publishedYes


  • Apoptosis
  • Aspergillus
  • Chromatin condensation
  • Fission yeast
  • NIMA


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