Genome wide analysis of Arabidopsis thaliana reveals a unique genetic arrangement of ACGT motif in the protein phosphatase 2C (PP2C) like promoter (accession number AT5G59220). In the present study, full length, 900 b...Genome wide analysis of Arabidopsis thaliana reveals a unique genetic arrangement of ACGT motif in the protein phosphatase 2C (PP2C) like promoter (accession number AT5G59220). In the present study, full length, 900 base pair, 500 base pair, 400 base pair and NRM deletion variants of PP2C like promoter were constructed to investigate the activity of PP2C like promoter in the presence of inducers like abscisic acid, jasmonic acid and salicylic acid. The PP2C promoter has three ACGT elements in close vicinity. They are so positioned that they are separated by a spacer of 30 base pair and 5 base pair respectively from each other. The study has shown that ACGTN30ACGT genetic architecture is essential for the promoter to be induced in response to abscisic acid. The synergistic and antagonistic effects of cis elements were observed. AACA is a positive regulatory element in endosperm and is known to act as negative regulatory element in other tissues. In this study AACA, have been found to negatively regulate the expression of reporter gene EGFP in both induced and under uninduced conditions.展开更多
Sugar signaling is a mechanism that plants use to integrate various internal and external cues to achieve nutrient homeostasis, mediate developmental programs, and articulate stress responses. Many bZlP transcription ...Sugar signaling is a mechanism that plants use to integrate various internal and external cues to achieve nutrient homeostasis, mediate developmental programs, and articulate stress responses. Many bZlP transcription factors are known to be involved in nutrient and/or stress signaling. An Arabidopsis Sl-group bZlP gene, AtbZIP1, was identified as a sugar-sensitive gene in a previous gene expression profiling study （Plant Cell. 16, 2128-2150）. In this report, we show that the expression of AtbZIP1 is repressed by sugars in a fast, sensitive, and reversible way. The sugar repression of Atb- ZIP1 is affected by a conserved sugar signaling component, hexokinase. Besides being a sugar-regulated gene, AtbZIP1 can mediate sugar signaling and affect gene expression, plant growth, and development. When carbon nutrients are limited, gain or loss of function of AtbZlP1 causes changes in the rates of early seedling establishment. Results of phenotypic analyses indicate that AtbZlP1 acts as a negative regulator of early seedling growth. Using gain- and loss-of-function plants in a microarray analysis, two sets of putative AtbZIP1-regulated genes have been identified. Among them, sugar-responsive genes are highly over-represented, implicating a role of AtbZlP1 in sugar-mediated gene expression. Using yeast two-hybrid （Y-2-H） screens and bimolecular fluorescence complementation （BiFC） analyses, we are able to recapitulate extensive C/S1 AtbZlP protein interacting network in living cells. Finally, we show that AtbZIP1 can bind ACGT-based motifs in vitro and that the binding characteristics appear to be affected by the heterodimerization between AtbZlP1 and the C-group AtbZIPs, including AtbZlP10 and AtbZlP63.展开更多
文摘Genome wide analysis of Arabidopsis thaliana reveals a unique genetic arrangement of ACGT motif in the protein phosphatase 2C (PP2C) like promoter (accession number AT5G59220). In the present study, full length, 900 base pair, 500 base pair, 400 base pair and NRM deletion variants of PP2C like promoter were constructed to investigate the activity of PP2C like promoter in the presence of inducers like abscisic acid, jasmonic acid and salicylic acid. The PP2C promoter has three ACGT elements in close vicinity. They are so positioned that they are separated by a spacer of 30 base pair and 5 base pair respectively from each other. The study has shown that ACGTN30ACGT genetic architecture is essential for the promoter to be induced in response to abscisic acid. The synergistic and antagonistic effects of cis elements were observed. AACA is a positive regulatory element in endosperm and is known to act as negative regulatory element in other tissues. In this study AACA, have been found to negatively regulate the expression of reporter gene EGFP in both induced and under uninduced conditions.
基金This work was supported by The National Science Foundation （IOB- 0543751 to J.C.J.）.We thank the Arabidopsis Biological Resource Center （Columbus, Ohio） for providing DNA clones and seeds, Dr Biao Ding formicroscopy facility, Dr Steven St Martin for microarray design and data analysis, Cyrus Hah for protoplast transient expression analysis, Drs John Finer and Michelle Jones for critical reading of the manuscript, and Joe Takayama for greenhouse support. No conflict of interest declared.
文摘Sugar signaling is a mechanism that plants use to integrate various internal and external cues to achieve nutrient homeostasis, mediate developmental programs, and articulate stress responses. Many bZlP transcription factors are known to be involved in nutrient and/or stress signaling. An Arabidopsis Sl-group bZlP gene, AtbZIP1, was identified as a sugar-sensitive gene in a previous gene expression profiling study （Plant Cell. 16, 2128-2150）. In this report, we show that the expression of AtbZIP1 is repressed by sugars in a fast, sensitive, and reversible way. The sugar repression of Atb- ZIP1 is affected by a conserved sugar signaling component, hexokinase. Besides being a sugar-regulated gene, AtbZIP1 can mediate sugar signaling and affect gene expression, plant growth, and development. When carbon nutrients are limited, gain or loss of function of AtbZlP1 causes changes in the rates of early seedling establishment. Results of phenotypic analyses indicate that AtbZlP1 acts as a negative regulator of early seedling growth. Using gain- and loss-of-function plants in a microarray analysis, two sets of putative AtbZIP1-regulated genes have been identified. Among them, sugar-responsive genes are highly over-represented, implicating a role of AtbZlP1 in sugar-mediated gene expression. Using yeast two-hybrid （Y-2-H） screens and bimolecular fluorescence complementation （BiFC） analyses, we are able to recapitulate extensive C/S1 AtbZlP protein interacting network in living cells. Finally, we show that AtbZIP1 can bind ACGT-based motifs in vitro and that the binding characteristics appear to be affected by the heterodimerization between AtbZlP1 and the C-group AtbZIPs, including AtbZlP10 and AtbZlP63.
