title: Repression of jasmonate signaling by a non-TIFY JAZ protein in Arabidopsis.
abstract: JAsmonate ZIM-domain (JAZ) proteins repress the activity of transcription factors that execute responses to the plant hormone jasmonoyl-L-isoleucine (JA-Ile). The ZIM protein domain recruits the co-repressors NINJA and TOPLESS to JAZ-bound transcription factors, and contains a highly conserved TIF[F/Y]XG motif that defines the larger family of TIFY proteins to which JAZs belong. Here, we report that diverse plant species contain genes encoding putative non-TIFY JAZ proteins, including a previously unrecognized JAZ repressor in Arabidopsis (JAZ13, encoded by At3g22275). JAZ13 is most closely related to JAZ8 and includes divergent EAR, TIFY/ZIM, and Jas motifs. Unlike JAZ8, however, JAZ13 contains a Ser-rich C-terminal tail that is a site for phosphorylation. Overexpression of JAZ13 resulted in reduced sensitivity to JA, attenuation of wound-induced expression of JA-response genes, and decreased resistance to insect herbivory. JAZ13 interacts with the bHLH transcription factor MYC2 and the co-repressor TOPLESS but, consistent with the absence of a TIFY motif, neither NINJA nor other JAZs. Analysis of single and higher-order T-DNA insertion jaz null mutants provided further evidence that JAZ13 is a repressor JA signaling. Our results demonstrate that proteins outside the TIFY family are functional JAZ repressors and further suggest that this expansion of the JAZ family allows fine-tuning of JA-mediated transcriptional responses.
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Thireault
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Shyu
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: St Aubin
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Marcelo L
authors.initials: ML
authors.lastname: Campos
authors.affiliation: Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.|Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
authors.forename: Gregg A
authors.initials: GA
authors.lastname: Howe
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007532:Isoleucine / Q000031:analogs & derivatives / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C532883:jasmonoyl-isoleucine; D007532:Isoleucine; C011006:jasmonic acid
keywords: Arabidopsis thaliana; JAsmonate-ZIM; TIFY protein; hormone signaling; jasmonate; lineage-specific gene; transcription