RRC ID 31364
Author Fukazawa J, Teramura H, Murakoshi S, Nasuno K, Nishida N, Ito T, Yoshida M, Kamiya Y, Yamaguchi S, Takahashi Y.
Title DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in regulation of gibberellin homeostasis and signaling in Arabidopsis.
Journal Plant Cell
Abstract Gibberellins (GAs) are essential regulators of plant development, and DELLAs are negative regulators of GA signaling. The mechanism of GA-dependent transcription has been explained by DELLA-mediated titration of transcriptional activators and their release through the degradation of DELLAs in response to GA. However, the effect of GA on genome-wide expression is predominantly repression, suggesting the existence of unknown mechanisms of GA function. In this study, we identified an Arabidopsis thaliana DELLA binding transcription factor, GAI-ASSOCIATED FACTOR1 (GAF1). GAF1 shows high homology to INDETERMINATE DOMAIN1 (IDD1)/ENHYDROUS. GA responsiveness was decreased in the double mutant gaf1 idd1, whereas it was enhanced in a GAF1 overexpressor. GAF1 binds to genes that are subject to GA feedback regulation. Furthermore, we found that GAF1 interacts with the corepressor TOPLESS RELATED (TPR) and that DELLAs and TPR act as coactivators and a corepressor of GAF1, respectively. GA converts the GAF1 complex from transcriptional activator to repressor via the degradation of DELLAs. These results indicate that DELLAs turn on or off two sets of GA-regulated genes via dual functions, namely titration and coactivation, providing a mechanism for the integrative regulation of plant growth and GA homeostasis.
Volume 26(7)
Pages 2920-38
Published 2014-7
DOI 10.1105/tpc.114.125690
PII tpc.114.125690
PMID 25035403
PMC PMC4145123
MeSH Antibodies Arabidopsis / cytology Arabidopsis / genetics* Arabidopsis / physiology Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism* Gene Expression Gene Expression Regulation, Plant* Genes, Reporter Gibberellins / metabolism* Homeostasis Mutagenesis, Insertional Plant Growth Regulators / metabolism* Plants, Genetically Modified Promoter Regions, Genetic / genetics Protein Binding Ribonuclease P / genetics Ribonuclease P / metabolism* Seedlings / cytology Seedlings / genetics Seedlings / physiology Signal Transduction Two-Hybrid System Techniques
IF 8.228
Times Cited 19
Arabidopsis / Cultured plant cells, genes rpc00008