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Analysing dynamical behavior of cellular networks via stochastic bifurcations.

Zakharova A, Kurths J, Vadivasova T, Koseska A - PLoS ONE (2011)

Bottom Line: The dynamical structure of genetic networks determines the occurrence of various biological mechanisms, such as cellular differentiation.However, the question of how cellular diversity evolves in relation to the inherent stochasticity and intercellular communication remains still to be understood.Moreover, we show that under changing stochastic conditions, the probabilities of expressing certain concentration values are different, leading to different functionality of the cells, and thus to differentiation of the cells in the various types.

View Article: PubMed Central - PubMed

Affiliation: Center for Dynamics of Complex Systems, University of Potsdam, Potsdam, Germany. zakharova-as@mail.ru

ABSTRACT
The dynamical structure of genetic networks determines the occurrence of various biological mechanisms, such as cellular differentiation. However, the question of how cellular diversity evolves in relation to the inherent stochasticity and intercellular communication remains still to be understood. Here, we define a concept of stochastic bifurcations suitable to investigate the dynamical structure of genetic networks, and show that under stochastic influence, the expression of given proteins of interest is defined via the probability distribution of the phase variable, representing one of the genes constituting the system. Moreover, we show that under changing stochastic conditions, the probabilities of expressing certain concentration values are different, leading to different functionality of the cells, and thus to differentiation of the cells in the various types.

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A simplified scheme of the genetic network under investigation.Mutually repressing genes  and  form the toggle switch inside separate cells. The  molecule denoted as , diffuses through the membrane, providing intercell coupling.
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pone-0019696-g001: A simplified scheme of the genetic network under investigation.Mutually repressing genes and form the toggle switch inside separate cells. The molecule denoted as , diffuses through the membrane, providing intercell coupling.

Mentions: The underlying genetic circuit (Fig. 1) contains a toggle switch composed of two genes, lacI, denoted here as u, and cI857 (v), that inhibit each other by repressing transcription from their respective promoters P and P. This circuit is known to lead to bistable behavior [15]. The promoter P also drives the expression of a third gene, luxI (w) that synthesizes a small autoinducer () molecule, which is able to diffuse in and out of the cell. The activates transcription of promoter P. Placing a second copy of the u gene under the control of this promoter provides both an additional feedback loop to the toggle switch, and a mechanism that couples the switch to all cells in the population via quorum sensing.


Analysing dynamical behavior of cellular networks via stochastic bifurcations.

Zakharova A, Kurths J, Vadivasova T, Koseska A - PLoS ONE (2011)

A simplified scheme of the genetic network under investigation.Mutually repressing genes  and  form the toggle switch inside separate cells. The  molecule denoted as , diffuses through the membrane, providing intercell coupling.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102061&req=5

pone-0019696-g001: A simplified scheme of the genetic network under investigation.Mutually repressing genes and form the toggle switch inside separate cells. The molecule denoted as , diffuses through the membrane, providing intercell coupling.
Mentions: The underlying genetic circuit (Fig. 1) contains a toggle switch composed of two genes, lacI, denoted here as u, and cI857 (v), that inhibit each other by repressing transcription from their respective promoters P and P. This circuit is known to lead to bistable behavior [15]. The promoter P also drives the expression of a third gene, luxI (w) that synthesizes a small autoinducer () molecule, which is able to diffuse in and out of the cell. The activates transcription of promoter P. Placing a second copy of the u gene under the control of this promoter provides both an additional feedback loop to the toggle switch, and a mechanism that couples the switch to all cells in the population via quorum sensing.

Bottom Line: The dynamical structure of genetic networks determines the occurrence of various biological mechanisms, such as cellular differentiation.However, the question of how cellular diversity evolves in relation to the inherent stochasticity and intercellular communication remains still to be understood.Moreover, we show that under changing stochastic conditions, the probabilities of expressing certain concentration values are different, leading to different functionality of the cells, and thus to differentiation of the cells in the various types.

View Article: PubMed Central - PubMed

Affiliation: Center for Dynamics of Complex Systems, University of Potsdam, Potsdam, Germany. zakharova-as@mail.ru

ABSTRACT
The dynamical structure of genetic networks determines the occurrence of various biological mechanisms, such as cellular differentiation. However, the question of how cellular diversity evolves in relation to the inherent stochasticity and intercellular communication remains still to be understood. Here, we define a concept of stochastic bifurcations suitable to investigate the dynamical structure of genetic networks, and show that under stochastic influence, the expression of given proteins of interest is defined via the probability distribution of the phase variable, representing one of the genes constituting the system. Moreover, we show that under changing stochastic conditions, the probabilities of expressing certain concentration values are different, leading to different functionality of the cells, and thus to differentiation of the cells in the various types.

Show MeSH