Deregulated cyclin E induces chromosome instability

Nature. 1999 Sep 16;401(6750):297-300. doi: 10.1038/45836.


Cyclin E, a regulatory subunit of cyclin-dependent kinase 2 (Cdk2), is an important regulator of entry into S phase in the mammalian cell cycle. In normal dividing cells, cyclin E accumulates at the G1/S-phase boundary and is degraded as cells progress through S phase. However, in many human tumours cyclin E is overexpressed and the levels of protein and kinase activity are often deregulated relative to the cell cycle. It is not understood how alterations in expression of cyclin E contribute to tumorigenesis. Here we show that constitutive cyclin-E overexpression in both immortalized rat embryo fibroblasts and human breast epithelial cells results in chromosome instability (CIN). In contrast, analogous expression of cyclin D1 or A does not increase the frequency of CIN. Cyclin-E-expressing cells that exhibit CIN have normal centrosome numbers. However, constitutive overexpression of cyclin E impairs S-phase progression, indicating that aberrant regulation of this process may be responsible for the CIN observed. These results indicate that downregulation of cyclin-E/Cdk2 kinase activity following the G1/S-phase transition may be necessary for the maintenance of karyotypic stability.

Publication types

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

MeSH terms

  • Animals
  • Breast Neoplasms / genetics
  • CDC2-CDC28 Kinases*
  • Cell Division
  • Cell Transformation, Neoplastic
  • Chromosome Aberrations*
  • Cyclin E / genetics
  • Cyclin E / metabolism*
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases / metabolism
  • Humans
  • Karyotyping
  • Mutation
  • Protein Serine-Threonine Kinases / metabolism
  • Rats
  • S Phase
  • Tumor Cells, Cultured


  • Cyclin E
  • Protein Serine-Threonine Kinases
  • CDC2-CDC28 Kinases
  • CDK2 protein, human
  • Cdk2 protein, rat
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases