Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA.
Nat Genet. 2011 Jun;43(6):554-60. doi: 10.1038/ng.821. Epub 2011 May 1.
Gene activity is described by the time series of discrete, stochastic mRNA production events. This transcriptional time series shows intermittent, bursty behavior. One consequence of this temporal intricacy is that gene expression can be tuned by varying different features of the time series. Here we quantify copy-number statistics of mRNA from 20 Escherichia coli promoters using single-molecule fluorescence in situ hybridization in order to characterize the general properties of these transcriptional time series. We find that the degree of burstiness is correlated with gene expression level but is largely independent of other parameters of gene regulation. The observed behavior can be explained by the underlying variation in the duration of bursting events. Using Shannon's mutual information function, we estimate the mutual information transmitted between an outside stimulus, such as the extracellular concentration of inducer molecules, and intracellular levels of mRNA. This suggests that the outside stimulus transmits information reflected in the properties of transcriptional time series.
基因活性是由离散的、随机的 mRNA 产生事件的时间序列来描述的。这个转录时间序列表现出间歇性的爆发行为。这种时间复杂性的一个后果是，通过改变时间序列的不同特征，可以对基因表达进行调整。在这里，我们使用单分子荧光原位杂交技术，对 20 个大肠杆菌启动子的 mRNA 进行了拷贝数统计，以表征这些转录时间序列的一般特性。我们发现，爆发程度与基因表达水平相关，但在很大程度上与基因调控的其他参数无关。观察到的行为可以用爆发事件持续时间的潜在变化来解释。我们使用香农互信息函数，估计了外部刺激（如胞外诱导分子浓度）与细胞内 mRNA 水平之间传递的互信息。这表明，外部刺激传递了反映在转录时间序列特性中的信息。
