title: Arabidopsis growth-regulating factor7 functions as a transcriptional repressor of abscisic acid- and osmotic stress-responsive genes, including DREB2A.
abstract: Arabidopsis thaliana DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN2A (DREB2A) functions as a transcriptional activator that increases tolerance to osmotic and heat stresses; however, its expression also leads to growth retardation and reduced reproduction. To avoid these adverse effects, the expression of DREB2A is predicted to be tightly regulated. We identified a short promoter region of DREB2A that represses its expression under nonstress conditions. Yeast one-hybrid screening for interacting factors identified GROWTH-REGULATING FACTOR7 (GRF7). GRF7 bound to the DREB2A promoter and repressed its expression. In both artificial miRNA-silenced lines and a T-DNA insertion line of GRF7, DREB2A transcription was increased compared with the wild type under nonstress conditions. A previously undiscovered cis-element, GRF7-targeting cis-element (TGTCAGG), was identified as a target sequence of GRF7 in the short promoter region of DREB2A via electrophoretic mobility shift assays. Microarray analysis of GRF7 knockout plants showed that a large number of the upregulated genes in the mutant plants were also responsive to osmotic stress and/or abscisic acid. These results suggest that GRF7 functions as a repressor of a broad range of osmotic stress-responsive genes to prevent growth inhibition under normal conditions.
authors.affiliation: Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: June-Sik
authors.initials: JS
authors.lastname: Kim
authors.forename: Junya
authors.initials: J
authors.lastname: Mizoi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kidokoro
authors.forename: Kyonoshin
authors.initials: K
authors.lastname: Maruyama
authors.forename: Jun
authors.initials: J
authors.lastname: Nakajima
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nakashima
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Mitsuda
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takiguchi
authors.forename: Masaru
authors.initials: M
authors.lastname: Ohme-Takagi
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kondou
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshizumi
authors.forename: Minami
authors.initials: M
authors.lastname: Matsui
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yamaguchi-Shinozaki
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques / Q000379:methods; D017343:Genes, Plant; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009995:Osmosis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; C114579:DREB2A protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000040:Abscisic Acid