An analytical study of the number of steady states in gene regulatory networks
An analytical study of the number of steady states in gene regulatory networks
复制标题
DOI：
10.1016/j.jtbi.2005.03.015
复制
发表时间：
2005-10-07
影响因子：
2
通讯作者：
Mochizuki, A
中科院分区：
文献类型：
--
作者：
Mochizuki, A
在此，我提出了一个基因网络模型，并通过数值和解析方法研究了基因网络动力学中的稳态。在该模型中，mRNA和蛋白水平随时间连续变化；每个基因根据转录因子的浓度改变转录调控。连续模型的动力学行为非常复杂，不同于离散模型布尔网络的动力学行为。该模型的大部分稳态可分为三类。对应于布尔函数的基因相互作用的大致结构，足以预测在这些类型的稳定状态下每个基因的表达水平。我还确定了在随机生成的基因网络中观察到的两种主要稳定状态的预期数量。从这些公式得到的结果与以前公认的信念相矛盾。结果表明，基因数量和基因之间的连通性都不会增加随机基因网络中稳定状态的预期数量。稳定状态的数量非常少。然而，自我调节基因的数量有效地增加了网络中稳定状态的数量。这些结果表明，基因数量的增加可能不是生物体内各种不同细胞类型进化的直接驱动力。相反，自我调节基因的数量可能会显著增加细胞多样性。(c) 2005 Elsevier Ltd版权所有。
Herein, I proposed a model for gene networks and studied the steady states in the dynamics both by numerical and analytical methods. In this model, mRNA and protein levels change continuously with time; each gene alters transcriptional regulation depending on the concentration of transcription factors. The dynamical behavior of continuous model is quite complex and different from that of the discrete model, the Boolean network. Large portion of steady states of this model can be classified into three types. The rough structure of gene interactions, which corresponds to Boolean function, is sufficient to predict the expression level of each gene in these types of steady states. I also determined the expected numbers of two major types of steady states observed in a randomly generated gene network. The results obtained from these formulae contradict previously accepted belief. The results are that neither gene number nor connectivity between genes increases the expected number of steady states in a random gene network. The number of steady states is very small. The number of self-regulatory genes, however, effectively increases the number of steady states in a network. These results imply that increases in gene number may not be the direct driving force for the evolution of a variety of different cell types within organisms. Instead, the number of self-regulatory genes may significantly increase cellular diversity. (c) 2005 Elsevier Ltd. All rights reserved.