title: DELLA protein functions as a transcriptional activator through the DNA binding of the indeterminate domain family proteins.
abstract: DELLA protein is a key negative regulator of gibberellin (GA) signaling. Although how DELLA regulates downstream gene expression remains unclear, DELLA has been proposed to function as a transcriptional activator. However, because DELLA lacks a DNA-binding domain, intermediate protein(s) mediating the DELLA/DNA interaction are believed to be necessary for activating DELLA target genes. Here, using yeast hybrid screenings, we identified five members of indeterminate domain (IDD) protein family which bind physically to both DELLA and the promoter sequence of the GA-positive regulator SCARECROW-LIKE 3 (SCL3), which previously was characterized as a DELLA direct target gene. Transient assays using Arabidopsis protoplasts demonstrated that a luciferase reporter controlled by the SCL3 promoter was additively transactivated by REPRESSOR of ga1-3 (RGA) and IDDs. Phenotypic analysis of transgenic plants expressing AtIDD3 (one of the 16 IDDs in the Arabidopsis genome) fused with the plant-specific repression domain (SRDX) supported the possibility that AtIDD3 is positively involved in GA signaling. In addition, we found that SCL3 protein also interacts with IDDs, resulting in the suppression of its target gene expression. In this context, DELLA and SCL3 interact competitively with IDD proteins to regulate downstream gene expression. These results suggest that the coregulators DELLA and SCL3, using IDDs as transcriptional scaffolds for DNA binding, antagonistically regulate the expression of their downstream targets to control the GA signaling pathway.
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Ko
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Sato
authors.affiliation: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan;
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Mitsuda
authors.affiliation: United Graduate School of Agricultural Sciences, Ehime University, Ehime 790-8566, Japan;
authors.forename: Mika
authors.initials: M
authors.lastname: Nomoto
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan;
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Maeo
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Eriko
authors.initials: E
authors.lastname: Koketsu
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Rie
authors.initials: R
authors.lastname: Mitani
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Kawamura
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan;
authors.forename: Sumie
authors.initials: S
authors.lastname: Ishiguro
authors.affiliation: Life Science Research Center, Institute of Research Promotion, Kagawa University, Kagawa 761-0795, Japan; and.
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Tada
authors.affiliation: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan;Institute for Environmental Science and Technology, Saitama University, Saitama 338-8770, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Ohme-Takagi
authors.affiliation: Bioscience and Biotechnology Center and.
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsuoka
authors.affiliation: Bioscience and Biotechnology Center and mueguchi@agr.nagoya-u.ac.jp.
authors.forename: Miyako
authors.initials: M
authors.lastname: Ueguchi-Tanaka
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D056970:Co-Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D056970:Co-Repressor Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; C109555:GAI protein, Arabidopsis; C112487:Id1 protein, plant; D010940:Plant Proteins; C000591169:SCL3 protein, Arabidopsis; D014157:Transcription Factors
keywords: coactivator/corepressor exchange regulation system; gibberellin feedback regulation; transcription factor