Genome-wide expression profiling of ARABIDOPSIS RESPONSE REGULATOR 7(ARR7) overexpression in cytokinin response

Mol Genet Genomics. 2007 Feb;277(2):115-37. doi: 10.1007/s00438-006-0177-x. Epub 2006 Oct 24.


The type-A ARRs of cytokinin two-component signaling system act as negative regulators for cytokinin signaling except for ARR4, but the molecular mechanism by which the A-type ARRs regulate cytokinin signaling remain elusive. To get insights into the molecular function of A-type ARR in cytokinin response, we sought to find the components that function downstream of A-type ARR protein by investigating the effects of ARR7 overexpression on cytokinin-regulated gene expression with the Affymetrix full genome array. To examine early cytokinin response, plants were treated with cytokinin for 30 min or 2 h, followed by GeneChip analysis. The hierarchical clustering analysis of our GeneChip data showed that ARR7 overexpression had distinctively repressive impacts on various groups of the cytokinin-regulated genes. In particular, the induction of all A-type ARRs except for ARR22, and AHK(ARABIDOPSIS HISTIDINE KINASE)1 and AHK4 was suppressed by ARR7. Cytokinin-induced expression of most of 12 expansin genes were repressed by ARR7, indicating potential involvement of ARR7 in cell expansion and plant development. Up-regulation of five cytokinin oxidase genes by cytokinins was negatively affected by ARR7. Our GeneChip analysis suggest that ARR7 mainly acts as a transcriptional repressor for a variety of early cytokinin-regulated genes encoding transcription factors, signal transmitters, plant development, and cellular metabolism, which may be responsible for reduced sensitivity of Arabidopsis transgenic plants overexpressing ARR7 to exogenous cytokinins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / drug effects
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Cytokinins / pharmacology*
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Drug Resistance / genetics
  • Gene Expression Profiling*
  • Gene Expression Regulation, Plant / drug effects*
  • Genome, Plant / drug effects
  • Oligonucleotide Array Sequence Analysis
  • Plants, Genetically Modified
  • Signal Transduction / drug effects
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transcription, Genetic
  • Transfection*


  • ARR7 protein, Arabidopsis
  • Arabidopsis Proteins
  • Cytokinins
  • DNA-Binding Proteins
  • Transcription Factors