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DY: Fachverband Dynamik und Statistische Physik

DY 7: Poster I

DY 7.12: Poster

Montag, 11. März 2013, 17:30–19:30, Poster C

Boolean and continuous networks with checkpoint states — •Danijel Komljenović¹, Tiago Peixoto², Eva Ackermann¹, and Barbara Drossel¹ — ¹Institut für Festkörperphysik, TU Darmstadt — ²Institut für theoretische Physik, Universität Bremen

Gene regulatory networks must function robustly in the presence of a stochastic environment and unreliable regulatory components. An observed mechanism employed by real organisms to fulfill this task is the enforcement of so-called "checkpoint states". This corresponds to a partial ordering of the dynamics where the trajectories cannot proceed from one checkpoint to the next until all requirements from the first checkpoint have been met. This guarantees a certain amount of predictability, while it leaves at the same time room for variation when the system moves between checkpoints. We show how such checkpoint dynamics can be explicitly constructed in a Boolean representation of gene regulatory dynamics. In this representation, a checkpoint is a state through which the dynamics must always go even when a fully stochastic update scheme is applied. Given a predefined set of checkpoints, we construct possible intermediary trajectories, and finally the ensemble of networks which fulfill it. We proceed by comparing the Boolean models with their continuous counterparts composed of differential equations describing in more detail the concentrations of proteins and mRNA. This allows us to identify the central criteria enabling the faithful reproduction of the Boolean dynamics in the continuous description, depending on the Hill coefficients of the continuous functions and the sequence of checkpoint states on the trajectory.