Thieffry D, Huerta A M, Pérez-Rueda E, Collado-Vides J
Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Morelos 62100, México.
Bioessays. 1998 May;20(5):433-40. doi: 10.1002/(SICI)1521-1878(199805)20:5<433::AID-BIES10>3.0.CO;2-2.
Because a large number of molecular mechanisms involved in gene regulation have been described during the last decades, it is now becoming possible to address questions about the global structure of gene regulatory networks, at least in the case of some of the best-characterized organisms. This paper presents a global characterization of the transcriptional regulation in Escherichia coli on the basis of the current data. The connectivity of the corresponding network was evaluated by analyzing the distribution of the number of genes regulated by a given regulatory protein, and the distribution of the number of regulatory genes regulating a given regulated gene. The mean connectivity found (between 2 and 3) shows a rather loosely interconnected structure. Special emphasis is given to circular sequences of interactions ("circuits") because of their critical dynamical properties. Only one-element circuits were found, in which negative autoregulation is the dominant architecture. These global properties are discussed in light of several pertinent theoretical approaches, as well as in terms of physiological and evolutionary considerations.
在过去几十年中，由于已经描述了大量参与基因调控的分子机制，现在至少对于一些特征最明确的生物体来说，探讨基因调控网络的全局结构问题成为可能。本文基于现有数据对大肠杆菌中的转录调控进行全局表征。通过分析给定调控蛋白调控的基因数量分布以及调控给定受调控基因的调控基因数量分布，评估了相应网络的连通性。所发现的平均连通性（在2到3之间）表明其结构相互连接较为松散。由于其关键的动力学特性，特别强调了相互作用的循环序列（“回路”）。仅发现了单元素回路，其中负向自调控是主要结构。结合几种相关的理论方法以及生理和进化方面的考虑，对这些全局特性进行了讨论。
