The expression of genes is inevitably subject to intracellular noise. Noise, for some regulatory networks, is constructive but detrimental to many others. The intensity of the noise is a determinant factor and the method of tuning it is of great value. In this study, we illustrated that the transcriptional delay in an incoherent feedforward loop (FFL) grants the target protein modulation the intensity of noise. Remarkably, for a wide range, the coefficient of variation (COV) of the target protein appeared to be about linear to the time span of the transcriptional delay. Without a noise-buffering method, the COV of the target protein is 0.455. While applying incoherent FFL, the COV reduced to 0.236. Then, it changed from 0.236 to 0.630 as the transcriptional delay raised from 0 to 1000 seconds. If we further increased the delay out of the linear range, the COV finally reached 0.779. In addition, we incorporated the distribution of the transcriptional delay in the delay stochastic simulation algorithm. This distribution is based on the experimental observation in the literature. The outcome suggested that the distributed delay slightly improved the ability of tuning noise. In conclusion, we demonstrated a noise-tuning method that altered only the intensity of noise without changing the deterministic steady-state behaviors. It is ready to be applied to various systems in the field of synthetic biology.

中文翻译：

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在蛋白质水平上调节噪声强度的实用方法。

基因的表达不可避免地受到细胞内噪声的影响。对于某些监管网络而言，噪声是建设性的，但对许多其他有害。噪声的强度是决定性因素，并且对其进行调整的方法具有重要的价值。在这项研究中，我们说明了在非相干前馈环（FFL）中的转录延迟使目标蛋白质调节获得了噪声强度。值得注意的是，在很宽的范围内，目标蛋白的变异系数（COV）似乎与转录延迟的时间跨度大致成线性关系。如果没有噪音缓冲方法，目标蛋白的COV为0.455。使用非相干FFL时，COV降低至0.236。然后，随着转录延迟从0秒增加到1000秒，它从0.236变为0.630。如果我们进一步将延迟增加到线性范围之外，则COV最终将达到0.779。此外，我们将转录延迟的分布纳入了延迟随机模拟算法中。该分布基于文献中的实验观察。结果表明，分布式延迟稍微提高了调谐噪声的能力。总之，我们演示了一种噪声调整方法，该方法仅更改噪声的强度，而不会更改确定性的稳态行为。准备将其应用于合成生物学领域的各种系统。结果表明，分布式延迟稍微提高了调谐噪声的能力。总之，我们演示了一种噪声调整方法，该方法仅更改噪声的强度，而不会更改确定性的稳态行为。准备将其应用于合成生物学领域的各种系统。结果表明，分布式延迟稍微提高了调谐噪声的能力。总之，我们演示了一种噪声调整方法，该方法仅更改噪声的强度，而不会更改确定性的稳态行为。准备将其应用于合成生物学领域的各种系统。