Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
Cell. 2011 Jul 8;146(1):105-18. doi: 10.1016/j.cell.2011.06.024.
A challenge of the synthetic biology approach is to use our understanding of a system to recreate a biological function with specific properties. We have applied this framework to bacterial enhancers, combining a driver, transcription factor binding sites, and a poised polymerase to create synthetic modular enhancers. Our findings suggest that enhancer-based transcriptional control depends critically and quantitatively on DNA looping, leading to complex regulatory effects when the enhancer cassettes contain additional transcription factor binding sites for TetR, a bacterial transcription factor. We show through a systematic interplay of experiment and thermodynamic modeling that the level of gene expression can be modulated to convert a variable inducer concentration input into discrete or step-like output expression levels. Finally, using a different DNA-binding protein (TraR), we show that the regulatory output is not a particular feature of the specific DNA-binding protein used for the enhancer but a general property of synthetic bacterial enhancers.
合成生物学方法面临的一个挑战是利用我们对系统的理解，用具有特定属性的生物功能来重建它。我们将这一框架应用于细菌增强子，将驱动元件、转录因子结合位点和处于预备状态的聚合酶结合起来，构建了合成的模块化增强子。我们的研究结果表明，基于增强子的转录调控在很大程度上取决于 DNA 环化，当增强子盒包含 TetR（一种细菌转录因子）的其他转录因子结合位点时，会导致复杂的调控效应。我们通过实验和热力学建模的系统相互作用表明，可以调节基因表达水平，将可变诱导剂浓度输入转换为离散或阶跃样的输出表达水平。最后，我们使用不同的 DNA 结合蛋白（TraR）表明，调控输出不是用于增强子的特定 DNA 结合蛋白的特定特征，而是合成细菌增强子的一般特性。
