Programmable Ligand Detection System in Plants through a Synthetic Signal Transduction Pathway
Programmable Ligand Detection System in Plants through a Synthetic Signal Transduction Pathway
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DOI：
10.1371/journal.pone.0016292
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发表时间：
2011-01-25
期刊：
影响因子：
3.7
通讯作者：
Medford, June I.
中科院分区：
文献类型：
--
作者：
Antunes, Mauricio S.;Morey, Kevin J.;Medford, June I.
背景：监测人类和自然环境中有意或无意引入的物质的需求尚未得到满足。一个长期追求的目标是使植物能够感知并对特定物质做出反应，以用作环境监测器。计算重新设计的周质结合蛋白（PBPs）提供了一种手段来设计受体中的高灵敏度和特异性配体传感能力。来自这些蛋白质的输入可以通过组氨酸激酶（HK）介导的信号传导与基因表达相关联。HK信号系统的组分在细菌和植物之间进化上是保守的。我们以前报道，在响应细胞分裂素介导的HK激活植物，细菌反应调节PhoB易位到细胞核和激活转录。此外，我们以前描述了一种植物的视觉反应系统，去绿化电路，阈值敏感的记者系统，产生的视觉反应，这是远程检测和quantitable.Methodology/主要调查结果：我们描述了组装和功能的一个完整的合成信号转导途径，在植物中的链接输入从计算重新设计的PBPs的视觉反应。为了检测细胞外配体，我们将计算重新设计的PBP靶向质外体。PBPs结合配体并对趋化蛋白Trg的细胞外结构域产生亲和力。我们实验性地开发了Trg融合蛋白，其结合配体-PBP复合物，并激活胞内PhoR，PhoB的HK同源物。然后，我们适应Trg-PhoR融合植物中的功能，表明在外部配体的存在下，PhoB易位到细胞核并激活转录。我们将此输入连接到去绿电路，创建一个检测器plant.Conclusions/Significance：我们的系统是模块化的，PBP理论上可以被设计为结合大多数小分子。因此，我们的系统经过改进，可以让植物作为一种简单而廉价的手段来监测人类周围的物质，如污染物，爆炸物或化学制剂。
Background: There is an unmet need to monitor human and natural environments for substances that are intentionally or unintentionally introduced. A long-sought goal is to adapt plants to sense and respond to specific substances for use as environmental monitors. Computationally re-designed periplasmic binding proteins (PBPs) provide a means to design highly sensitive and specific ligand sensing capabilities in receptors. Input from these proteins can be linked to gene expression through histidine kinase (HK) mediated signaling. Components of HK signaling systems are evolutionarily conserved between bacteria and plants. We previously reported that in response to cytokinin-mediated HK activation in plants, the bacterial response regulator PhoB translocates to the nucleus and activates transcription. Also, we previously described a plant visual response system, the de-greening circuit, a threshold sensitive reporter system that produces a visual response which is remotely detectable and quantifiable.Methodology/Principal Findings: We describe assembly and function of a complete synthetic signal transduction pathway in plants that links input from computationally re-designed PBPs to a visual response. To sense extracellular ligands, we targeted the computational re-designed PBPs to the apoplast. PBPs bind the ligand and develop affinity for the extracellular domain of a chemotactic protein, Trg. We experimentally developed Trg fusions proteins, which bind the ligand-PBP complex, and activate intracellular PhoR, the HK cognate of PhoB. We then adapted Trg-PhoR fusions for function in plants showing that in the presence of an external ligand PhoB translocates to the nucleus and activates transcription. We linked this input to the de-greening circuit creating a detector plant.Conclusions/Significance: Our system is modular and PBPs can theoretically be designed to bind most small molecules. Hence our system, with improvements, may allow plants to serve as a simple and inexpensive means to monitor human surroundings for substances such as pollutants, explosives, or chemical agents.