The plant-specific cyclin-dependent kinase CDKB1;1 and transcription factor E2Fa-DPa control the balance of mitotically dividing and endoreduplicating cells in Arabidopsis

Plant Cell. 2004 Oct;16(10):2683-92. doi: 10.1105/tpc.104.024398. Epub 2004 Sep 17.


Transgenic Arabidopsis thaliana plants overproducing the E2Fa-DPa transcription factor have two distinct cell-specific phenotypes: some cells divide ectopically and others are stimulated to endocycle. The decision of cells to undergo extra mitotic divisions has been postulated to depend on the presence of a mitosis-inducing factor (MIF). Plants possess a unique class of cyclin-dependent kinases (CDKs; B-type) for which no ortholog is found in other kingdoms. The peak of CDKB1;1 activity around the G2-M boundary suggested that it might be part of the MIF. Plants that overexpressed a dominant negative allele of CDKB1;1 underwent enhanced endoreduplication, demonstrating that CDKB1;1 activity was required to inhibit the endocycle. Moreover, when the mutant CDKB1;1 allele was overexpressed in an E2Fa-DPa-overproducing background, it enhanced the endoreduplication phenotype, whereas the extra mitotic cell divisions normally induced by E2Fa-DPa were repressed. Surprisingly, CDKB1;1 transcription was controlled by the E2F pathway, as shown by its upregulation in E2Fa-DPa-overproducing plants and mutational analysis of the E2F binding site in the CDKB1;1 promoter. These findings illustrate a cross talking mechanism between the G1-S and G2-M transition points.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / cytology
  • Arabidopsis / enzymology
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Base Sequence
  • Cell Cycle Proteins / metabolism*
  • Cyclin-Dependent Kinases / metabolism*
  • DNA Primers
  • DNA-Binding Proteins / metabolism*
  • E2F Transcription Factors
  • Mitosis*
  • Plant Leaves / cytology
  • Plant Leaves / enzymology
  • Plant Leaves / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • Cell Cycle Proteins
  • DNA Primers
  • DNA-Binding Proteins
  • E2F Transcription Factors
  • Transcription Factors
  • Cyclin-Dependent Kinases