Universidad de Guadalajara, Centro Universitario de Ciencias de la Salud, Sierra Mojada 201, 44348 Guadalajara Jal, México.
J Theor Biol. 2010 Apr 7;263(3):340-52. doi: 10.1016/j.jtbi.2009.12.005. Epub 2009 Dec 22.
Oscillatory behaviour in the tryptophan operon of an Escherichia coli mutant strain lacking the enzyme-inhibition regulatory mechanism has been observed by Bliss et al. but not confirmed by others. This behaviour could be important from the standpoint of synthetic biology, whose goals include the engineering of intracellular genetic oscillators. This work is devoted to investigating, from a mathematical modelling point of view, the possibility that the trp operon of the E. coli inhibition-free strain expresses cyclically. For that we extend a previously introduced model for the regulatory pathway of the tryptophan operon in Escherichia coli to account for the observed multiplicity and cooperativity of repressor binding sites. Thereafter we investigate the model dynamics using deterministic numeric solutions, stochastic simulations, and analytic studies. Our results suggest that a quasi-periodic behaviour could be observed in the trp operon expression level of single bacteria.
布利斯等人观察到，缺乏酶抑制调节机制的大肠杆菌突变株色氨酸操纵子表现出振荡行为，但其他人并未证实这一行为。从合成生物学的角度来看，这种行为可能很重要，其目标包括设计细胞内遗传振荡器。这项工作致力于从数学建模的角度研究大肠杆菌无抑制菌株的色氨酸操纵子是否可能周期性表达。为此，我们扩展了之前介绍的大肠杆菌色氨酸操纵子调控途径模型，以解释观察到的阻遏物结合位点的多重性和协同性。然后，我们使用确定性数值解、随机模拟和分析研究来研究模型动力学。我们的结果表明，在单个细菌的色氨酸操纵子表达水平上可能观察到准周期性行为。
