Members of the GCN5 histone acetyltransferase complex regulate PLETHORA-mediated root stem cell niche maintenance and transit amplifying cell proliferation in Arabidopsis

Plant Cell. 2009 Apr;21(4):1070-9. doi: 10.1105/tpc.108.065300. Epub 2009 Apr 17.

Abstract

The PLETHORA (PLT) stem cell transcription factors form a developmentally instructive protein gradient in Arabidopsis thaliana roots. Histone acetylation is known to facilitate gene transcription and plays an important role in developmental processes. Here, we show that histone acetyltransferase GCN5 (for general control nonderepressible 5) attenuates the PLT gradient. Based on genetic evidence, we establish that GCN5 is essential for root stem cell niche maintenance and acts in the PLT pathway. The GCN5-associated factor ADA2b (for alteration/deficiency in activation 2b) is also positioned in the PLT pathway and regulates PLT expression, similar to GCN5. Both GCN5 and ADA2b mediate proliferation of the transit amplifying cells, but ADA2b does not affect stem cell niche maintenance. Overexpression of PLT2 rescues the stem cell niche defect of gcn5 mutants, indicating that GCN5 regulation of PLT expression is essential for maintenance of the root stem cell niche. We conclude that histone acetylation complexes play an important role in shaping a developmentally instructive gradient in the root.

MeSH terms

  • Arabidopsis / cytology*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology*
  • Cell Proliferation*
  • Histone Acetyltransferases
  • Plant Roots / cytology
  • Plant Roots / genetics
  • Plant Roots / metabolism
  • Signal Transduction
  • Stem Cells / cytology
  • Stem Cells / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*

Substances

  • ADA2b protein, Arabidopsis
  • Arabidopsis Proteins
  • PLT2 protein, Arabidopsis
  • Transcription Factors
  • GCN5 protein, Arabidopsis
  • Histone Acetyltransferases