MEDIATOR25 acts as an integrative hub for the regulation of jasmonate-responsive gene expression in Arabidopsis

Volkan Çevik, Brendan N Kidd, Peijun Zhang, Claire Hill, Steve Kiddle, Katherine J Denby, Eric B Holub, David M Cahill, John M Manners, Peer M Schenk, Jim Beynon, Kemal Kazan

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134 Citations (Scopus)

Abstract

The PHYTOCHROME AND FLOWERING TIME1 gene encoding the MEDIATOR25 (MED25) subunit of the eukaryotic Mediator complex is a positive regulator of jasmonate (JA)-responsive gene expression in Arabidopsis (Arabidopsis thaliana). Based on the function of the Mediator complex as a bridge between DNA-bound transcriptional activators and the RNA polymerase II complex, MED25 has been hypothesized to function in association with transcriptional regulators of the JA pathway. However, it is currently not known mechanistically how MED25 functions to regulate JA-responsive gene expression. In this study, we show that MED25 physically interacts with several key transcriptional regulators of the JA signaling pathway, including the APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) transcription factors OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59 and ERF1 as well as the master regulator MYC2. Physical interaction detected between MED25 and four group IX AP2/ERF transcription factors was shown to require the activator interaction domain of MED25 as well as the recently discovered Conserved Motif IX-1/EDLL transcription activation motif of MED25-interacting AP2/ERFs. Using transcriptional activation experiments, we also show that OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59- and ERF1-dependent activation of PLANT DEFENSIN1.2 as well as MYC2-dependent activation of VEGETATIVE STORAGE PROTEIN1 requires a functional MED25. In addition, MED25 is required for MYC2-dependent repression of pathogen defense genes. These results suggest an important role for MED25 as an integrative hub within the Mediator complex during the regulation of JA-associated gene expression.

Original languageEnglish
Pages (from-to)541-555
Number of pages15
JournalPlant Physiology
Volume160
Issue number1
DOIs
Publication statusPublished - Sep 2012

Keywords

  • Acetates
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Arabidopsis
  • Arabidopsis Proteins
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Conserved Sequence
  • Cyclopentanes
  • Gene Expression Regulation, Plant
  • Genes, Plant
  • Homeodomain Proteins
  • Molecular Sequence Data
  • Nuclear Proteins
  • Oxylipins
  • Protein Binding
  • Protein Interaction Mapping
  • Receptors, Cell Surface
  • Signal Transduction
  • Transcription Factors
  • Transcriptional Activation
  • Two-Hybrid System Techniques
  • Journal Article
  • Research Support, Non-U.S. Gov't

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  • Cite this

    Çevik, V., Kidd, B. N., Zhang, P., Hill, C., Kiddle, S., Denby, K. J., Holub, E. B., Cahill, D. M., Manners, J. M., Schenk, P. M., Beynon, J., & Kazan, K. (2012). MEDIATOR25 acts as an integrative hub for the regulation of jasmonate-responsive gene expression in Arabidopsis. Plant Physiology, 160(1), 541-555. https://doi.org/10.1104/pp.112.202697