Rice Homeobox Transcription Factor HOX1a Positively Regulates Gibberellin Responses by Directly Suppressing EL1

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 H...

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Bibliographic Details
Published in:Journal of integrative plant biology 2011-11, Vol.53 (11), p.869-878
Main Authors: Wen, Bi-Qing, Xing, Mei-Qing, Zhang, Hua, Dai, Cheng, Xue, Hong-Wei
Format: Article
Language:English
Subjects:
Chromatin
EL1
Gibberellins - pharmacology
giberellin
giberellin signaling
homeobox
Homeodomain Proteins - genetics
Homeodomain Proteins - metabolism
HOX1a
Oryza - drug effects
Oryza - genetics
Oryza - metabolism
Oryza sativa
Plant Growth Regulators - pharmacology
Plant Proteins - genetics
Plant Proteins - metabolism
Plants, Genetically Modified - drug effects
Plants, Genetically Modified - genetics
Plants, Genetically Modified - metabolism
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Summary: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.
ISSN:1672-9072
1744-7909
DOI:10.1111/j.1744-7909.2011.01075.x