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 prot...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 HOXla resulted in enhanced gibberellin （GA） response, indicating a positive effect of HOXla in GA signaling. HOXla is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOXla 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 HOXla directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOXla functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling.展开更多
基金supported by the Chinese Academy of Sciences (KSCX2-YW-N-058, KSCX2-YW-N-016)the National Natural Science Foundation of China (30570992)a project (2008ZX08009-003) from the Ministry of Agriculture of China for Transgenic Research
文摘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 HOXla resulted in enhanced gibberellin （GA） response, indicating a positive effect of HOXla in GA signaling. HOXla is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOXla 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 HOXla directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOXla functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling.
