1. Rice Homeobox Transcription Factor HOX1a Positively Regulates Gibberellin Responses by Directly Suppressing EL1F
- Author
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Mei-Qing Xing, Cheng Dai, Hong-Wei Xue, Hua Zhang, and Bi-Qing Wen
- Subjects
Homeodomain Proteins ,Genetics ,Regulator ,Oryza ,Promoter ,Plant Science ,Biology ,Plants, Genetically Modified ,Biochemistry ,Gibberellins ,General Biochemistry, Genetics and Molecular Biology ,Cell biology ,Plant Growth Regulators ,Transcription (biology) ,Homeobox ,Electrophoretic mobility shift assay ,Signal transduction ,Chromatin immunoprecipitation ,Transcription factor ,Plant Proteins - Abstract
Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox proteins have been identified. We here show that overexpression of rice homeobox gene HOX1a resulted in enhanced gibberellin (GA) response, indicating a positive effect of HOX1a in GA signaling. HOX1a is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOX1a suppresses the transcription of early flowering1 (EL1), a negative regulator of GA signaling, and further electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that HOX1a directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOX1a functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling.
- Published
- 2011
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