Promotive effect of brassinosteroids on cell division involves a distinct CycD3-induction pathway in Arabidopsis

Plant J. 2000 Dec;24(5):693-701. doi: 10.1046/j.1365-313x.2000.00915.x.


Brassinosteroids (BRs) are steroid hormones that play an essential role in plant growth and development. However, the contradictory results of previous studies make their role in cell division unclear. Using a cDNA array, we identified genes that respond to BR in the det2 suspension culture of Arabidopsis, and found that epi-brassinolide upregulated transcription of the CycD3, a D-type plant cyclin gene through which cytokinin activates cell division. RNA gel-blot analysis and cell culturing showed that epi-brassinolide may promote cell division through CycD3, and can substitute cytokinin in culturing of Arabidopsis callus and suspension cells. The CycD3 induction by epi-brassinolide was further shown to involve de novo protein synthesis, but no protein phosphorylation or dephosphorylation. Induction was also found to occur in cells of a BR-insensitive mutant, bri1, suggesting that BR induces CycD3 transcription through a previously unknown signal pathway in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / cytology
  • Arabidopsis / drug effects*
  • Arabidopsis / genetics
  • Brassinosteroids
  • Cell Division / drug effects*
  • Cholestanols / pharmacology*
  • Cyclins / genetics*
  • Cyclins / physiology
  • Cytokinins / pharmacology
  • DNA, Complementary / genetics
  • Gene Expression Regulation / drug effects
  • Oligonucleotide Array Sequence Analysis
  • Plant Growth Regulators / pharmacology*
  • RNA, Plant / drug effects
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • Signal Transduction
  • Steroids, Heterocyclic / pharmacology*
  • Transcription, Genetic / drug effects
  • Zeatin / pharmacology


  • Brassinosteroids
  • Cholestanols
  • Cyclins
  • Cytokinins
  • DNA, Complementary
  • Plant Growth Regulators
  • RNA, Plant
  • Steroids, Heterocyclic
  • Zeatin
  • brassinolide