Characterization of the AtSPX3 Promoter Elucidates its Complex Regulation in Response to Phosphorus Deficiency
Characterization of the AtSPX3 Promoter Elucidates its Complex Regulation in Response to Phosphorus Deficiency
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AtSPX3 启动子的表征阐明了其响应磷缺乏的复杂调节
DOI：
10.1093/pcp/pcw100
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发表时间：
2016
影响因子：
4.9
通讯作者：
Ling Hong-Qing
中科院分区：
文献类型：
--
作者：
Li Ye;Wu Huilan;Fan Huajie;Zhao Ting;Ling Hong-Qing
AtSPX3是拟南芥中参与磷胁迫动态平衡的重要基因，通过其表达来响应磷的缺乏。为了了解其转录调控，我们通过预测顺式元件的末端截断、内部缺失和突变来表征AtSPX3启动子，并鉴定了与PI状态相关的多个顺式元件。在AtSPX3启动子中，P1BS(AtPHR结合位点)和AtMyb4(可能的MYB4结合位点)是两个主要的元件。在缺磷条件下，P1BS对激活该基因的表达具有剂量效应，而AtMyb4元件具有双重功能：一是在缺磷条件下促进根中AtSPX3的表达，二是在缺磷和缺磷条件下抑制AtSPX3在地上部的表达。此外，我们还证实了植物PI动态平衡的关键转录因子AtPHR1对于AtMyb4元件在新梢中的负调控功能是必需的。此外，我们还发现AtSPX3启动子对激活基因表达有一定的长度限制。总的来说，我们在这项工作中的发现有助于理解参与PI摄取和动态平衡的基因的分子调控机制。
AtSPX3, responding to phosphate (Pi) deficiency by its expression, is an important gene involved in Pi homeostasis in Arabidopsis. To understand its transcriptional regulation, we characterized theAtSPX3promoter by distal truncation, internal deletion and mutation of the predictedcis-elements, and identified multiplecis-elements responsive to Pi status. The P1BS (AtPHR-binding site) and AtMyb4 (putative MYB4-binding site) elements were two maincis-elements in theAtSPX3promoter. P1BS is essential and has a dosage effect for activating expression of the gene under Pi deficiency, while the element AtMyb4 possesses a dual function: one is to enhanceAtSPX3expression in roots under Pi deficiency, and the other one is to repressAtSPX3expression in shoots under both Pi deficiency and sufficiency. Moreover, we confirmed that AtPHR1, a key transcription factor in Pi homeostasis of plants, was required for the negative regulation function of the AtMyb4 element in shoots. Additionally, we also found that theAtSPX3promoter had a length limitation for activating gene expression. Generally, our findings in this work are useful for understanding the molecular regulation mechanism of genes involved in Pi uptake and homeostasis.