The Timing of Transcriptional Regulation in Synthetic Gene Circuits.
The Timing of Transcriptional Regulation in Synthetic Gene Circuits.
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DOI：
10.1021/acssynbio.7b00118
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发表时间：
2017-11-17
影响因子：
4.7
通讯作者：
Bennett MR
中科院分区：
文献类型：
--
作者：
Cheng YY;Hirning AJ;Josić K;Bennett MR
转录因子及其靶启动子是合成生物学的核心。通过将这些组件排列成新颖的基因调控电路，合成生物学家已经能够创造出多种表型，包括双稳态开关、振荡器和逻辑门。然而，转录因子 (TF) 不会立即调节下游靶标。编码 TF 的基因开启后，该基因必须首先被转录，转录本必须被翻译，并且必须积累足够的 TF 以结合目标启动子的操纵位点。完成这一过程的时间（这里称为“信号时间”）是动态监管网络设计中的一个关键方面，但它的特征仍然很差。在这项工作中，我们测量了合成生物学中常用的大肠杆菌中两种 TF 的信号传导时间：激活剂 AraC 和阻抑剂 LacI。我们发现信号传导时间可以从几分钟到几十分钟不等，并且受到 TF 表达率的影响。我们的单细胞数据还表明，信号时间的变异性随着其平均值的增加而增加。为了验证这些信号时间测量，我们构建了一个两步遗传级联，并表明整个级联的信号时间可以根据其组成步骤来预测。这些结果为活细胞转录调控的时间尺度提供了具体的估计，这对于理解合成转录基因回路的动态非常重要。
Transcription factors and their target promoters are central to synthetic biology. By arranging these components into novel gene regulatory circuits, synthetic biologists have been able to create a wide variety of phenotypes, including bistable switches, oscillators, and logic gates. However, transcription factors (TFs) do not instantaneously regulate downstream targets. After the gene encoding a TF is turned on, the gene must first be transcribed, the transcripts must be translated, and sufficient TF must accumulate in order to bind operator sites of the target promoter. The time to complete this process, here called the “signaling time,” is a critical aspect in the design of dynamic regulatory networks, yet it remains poorly characterized. In this work, we measured the signaling time of two TFs in Escherichia coli commonly used in synthetic biology: the activator AraC and the repressor LacI. We found that signaling times can range from a few to tens of minutes, and are affected by the expression rate of the TF. Our single-cell data also show that the variability of the signaling time increases with its mean. To validate these signaling time measurements, we constructed a two-step genetic cascade, and showed that the signaling time of the full cascade can be predicted from those of its constituent steps. These results provide concrete estimates for the timescales of transcriptional regulation in living cells, which are important for understanding the dynamics of synthetic transcriptional gene circuits.
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影响因子：
64.8
作者：
通讯作者：
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影响因子：
8.6
作者：
Gupta C;López JM;Ott W;Josić K;Bennett MR
通讯作者：
Bennett MR
影响因子：
56.9
作者：
Elf, Johan;Li, Gene-Wei;Xie, X. Sunney
通讯作者：
Xie, X. Sunney
影响因子：
4.3
作者：
Josić K;López JM;Ott W;Shiau L;Bennett MR
通讯作者：
Bennett MR
DOI：
10.1073/pnas.1205693109
发表时间：
2012-10-16
影响因子：
11.1
作者：
Egbert, Robert G.;Klavins, Eric
通讯作者：
Klavins, Eric