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: June-Sik Kim, Junya Mizoi, Satoshi Kidokoro, Kyonoshin Maruyama, Jun Nakajima, Kazuo Nakashima, Nobutaka Mitsuda, Yuko Takiguchi, Masaru Ohme-Takagi, Youichi Kondou, Takeshi Yoshizumi, Minami Matsui, Kazuo Shinozaki, Kazuko Yamaguchi-Shinozaki
• Journal: The Plant cell (Plant Cell) Vol. 24 Issue 8 Pg. 3393-405 (Aug 2012) ISSN: 1532-298X [Electronic] England
• PMID: 22942381 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Arabidopsis Proteins
• DREB2A protein, Arabidopsis
• Recombinant Fusion Proteins
• Repressor Proteins
• Trans-Activators
• Transcription Factors
• Abscisic Acid

Topics

• Abscisic Acid (pharmacology)
• Arabidopsis (drug effects, genetics, metabolism)
• Arabidopsis Proteins (genetics, metabolism)
• Base Sequence
• Electrophoretic Mobility Shift Assay
• Gene Expression Regulation, Plant
• Gene Knockout Techniques (methods)
• Genes, Plant
• Genetic Vectors (genetics, metabolism)
• Molecular Sequence Data
• Osmosis
• Promoter Regions, Genetic
• Protein Binding
• Protein Structure, Tertiary
• Recombinant Fusion Proteins (genetics, metabolism)
• Repressor Proteins (genetics, metabolism)
• Stress, Physiological
• Trans-Activators (genetics, metabolism)
• Transcription Factors (genetics, metabolism)
• Transcription, Genetic
• Transcriptional Activation
• Two-Hybrid System Techniques
• Up-Regulation