title: MEDIATOR25 acts as an integrative hub for the regulation of jasmonate-responsive gene expression in Arabidopsis.
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.
authors: School of Life Sciences, University of Warwick, Wellesbourne, Warwick CV35 9EF, United Kingdom. volkan.cevik@sainsburylaboratory.ac.uk
authors: Volkan
authors: V
authors: Çevik
authors: Brendan N
authors: BN
authors: Kidd
authors: Peijun
authors: P
authors: Zhang
authors: Claire
authors: C
authors: Hill
authors: Steve
authors: S
authors: Kiddle
authors: Katherine J
authors: KJ
authors: Denby
authors: Eric B
authors: EB
authors: Holub
authors: David M
authors: DM
authors: Cahill
authors: John M
authors: JM
authors: Manners
authors: Peer M
authors: PM
authors: Schenk
authors: Jim
authors: J
authors: Beynon
authors: Kemal
authors: K
authors: Kazan
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D003517:Cyclopentanes / Q000494:pharmacology*; D004268:DNA-Binding Proteins; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D054883:Oxylipins / Q000494:pharmacology*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
chemical_list: C499534:APETALA2 protein, Arabidopsis; D000085:Acetates; D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D003517:Cyclopentanes; D004268:DNA-Binding Proteins; C494590:ETR1 protein, Arabidopsis; D018398:Homeodomain Proteins; C473611:MYC2 protein, Arabidopsis; D009687:Nuclear Proteins; C531343:ORA59 protein, Arabidopsis; D054883:Oxylipins; C475686:PFT1 protein, Arabidopsis; D011956:Receptors, Cell Surface; D014157:Transcription Factors; C072239:methyl jasmonate