Goryachev A B, Toh D J, Lee T
Systems Biology Group, Bioinformatics Institute, 30 Biopolis Str., Singapore 138671, Singapore.
Biosystems. 2006 Feb-Mar;83(2-3):178-87. doi: 10.1016/j.biosystems.2005.04.006. Epub 2005 Sep 19.
Understanding the relationship between the structural organization of intracellular decision networks and the observable phenotypes they control is one of the exigent problems of modern systems biology. Here we perform a systems analysis of a prototypic quorum sensing network whose operation allows bacterial populations to activate certain patterns of gene expression cooperatively. We apply structural perturbations to the model and analyze the resulting changes in the network behavior with the aim to identify the contribution of individual network elements to the functional fitness of the whole network. Specifically, we demonstrate the importance of the dimerization of the transcription factor and the presence of the auxiliary positive feedback loop on the switch-like behavior of the network and the stability of its "on" and "off" states under the influence of molecular noise.
理解细胞内决策网络的结构组织与其所控制的可观察表型之间的关系,是现代系统生物学中亟待解决的问题之一。在此,我们对一个原型群体感应网络进行了系统分析,该网络的运作使细菌群体能够协同激活特定的基因表达模式。我们对模型施加结构扰动,并分析网络行为由此产生的变化,目的是确定各个网络元件对整个网络功能适应性的贡献。具体而言,我们证明了转录因子二聚化以及辅助正反馈回路的存在对于网络的开关式行为以及在分子噪声影响下其“开”和“关”状态的稳定性的重要性。