Title: Noise as a selection criterion in gene regulatory networks
Authors: Tolga Cagatay, Marc Turcotte, Gurol Suel, Michael Elowitz, Jordi Garcia-Ojalvo
Abstract:Dynamical processes within cells can often be generated by different gene regulation circuits with distinct coupling architectures. One might then wonder what are the criteria that determine why a particular circuit architecture is selected by nature over another. Here we investigate this issue in the excitable genetic circuit that drives transient differentiation towards competence in the bacterium B. subtilis. Interestingly, the architecture of this excitable circuit is very different from standard excitable systems in other fields, such as neurobiology and surface chemistry. How did this novel excitable architecture emerge? We have addressed this problem by means of a combination of single-cell tracking via time-lapse fluorescence microscopy, biochemical assays, and mathematical modeling, and found that the natural competence architecture maximizes noise in the dynamics of the circuit, and that this higher level of random fluctuations helps the cells to cope with the environmental uncertainty associated with the stress conditions that drive the competence phenotype.
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