Spatiotemporal control of gene expression with pulse-generating networks
Spatiotemporal control of gene expression with pulse-generating networks
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DOI：
10.1073/pnas.0307571101
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发表时间：
2004-04-27
影响因子：
11.1
通讯作者：
Weiss, R
中科院分区：
文献类型：
--
作者：
Basu, S;Mehreja, R;Weiss, R
新兴合成生物学领域的重要挑战之一是设计能够在细胞群落中实现协调行为的人工网络。在这里，我们提出了一个合成的多细胞细菌系统，其中接收细胞表现出短暂的基因表达，以响应来自相邻发送细胞的持久信号。工程发送细胞合成的诱导剂，酰基高丝氨酸内酯（阿勒），自由扩散到空间上接近的接收细胞。接收器单元包含一个脉冲发生器电路，该电路包含一个前馈调节基序。该回路通过瞬时激活然后抑制GFP的表达来响应阿勒水平的长期增加。基于仿真模型，我们设计了脉冲发生器电路的变体，这些变体表现出不同的定量响应，例如脉冲的持续时间和强度增加。正如我们的模型和实验所示，脉冲的最大幅度和时间不仅取决于最终诱导剂浓度，而且还取决于其增加速率。区分诱导物浓度的各种增加速率的能力为在固体培养基上生长的细胞提供了独特的时空行为。具体来说，接收器细胞可以响应来自附近发送器细胞的通信，而完全忽略来自更远的接收器细胞的通信，尽管阿勒浓度最终在任何地方都达到高水平。由于类似于自然发生的前馈图案，脉冲发生器可以作为一个模型，以提高我们对这种系统的理解。
One of the important challenges in the emerging field of synthetic biology is designing artificial networks that achieve coordinated behavior in cell communities. Here we present a synthetic multicellular bacterial system where receiver cells exhibit transient gene expression in response to a long-lasting signal from neighboring sender cells. The engineered sender cells synthesize an inducer, an acyl-homoserine lactone (AHL), which freely diffuses to spatially proximate receiver cells. The receiver cells contain a pulse-generator circuit that incorporates a feed-forward regulatory motif. The circuit responds to a long-lasting increase in the level of AHL by transiently activating, and then repressing, the expression of a GFP. Based on simulation models, we engineered variants of the pulse-generator circuit that exhibit different quantitative responses such as increased duration and intensity of the pulse. As shown by our models and experiments, the maximum amplitude and timing of the pulse depend not only on the final inducer concentration, but also on its rate of increase. The ability to differentiate between various rates of increase in inducer concentrations affords the system a unique spatiotemporal behavior for cells grown on solid media. Specifically, receiver cells can respond to communication from nearby sender cells while completely ignoring communication from senders cells further away, despite the fact that AHL concentrations eventually reach high levels everywhere. Because of the resemblance to naturally occurring feed-forward motifs, the pulse generator can serve as a model to improve our understanding of such systems.