This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bundschuh, R. Articles by Jayaprakash, C. Search for Related Content PubMed PubMed Citation Articles by Bundschuh, R. Articles by Jayaprakash, C.

Fluctuations and Slow Variables in Genetic Networks

Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 USA

Correspondence: Address reprint requests to R. Bundschuh, E-mail: bundschuh{at}mps.ohio-state.edu.

Computer simulations of large genetic networks are often extremely time consuming because, in addition to the biologically interesting translation and transcription reactions, many less interesting reactions like DNA binding and dimerizations have to be simulated. It is desirable to use the fact that the latter occur on much faster timescales than the former to eliminate the fast and uninteresting reactions and to obtain effective models of the slow reactions only. We use three examples of self-regulatory networks to show that the usual reduction methods where one obtains a system of equations of the Hill type fail to capture the fluctuations that these networks exhibit due to the small number of molecules; moreover, they may even miss describing the behavior of the average number of proteins. We identify the inclusion of fast-varying variables in the effective description as the cause for the failure of the traditional schemes. We suggest a different effective description, which entails the introduction of an additional species, not present in the original networks, that is slowly varying. We show that this description allows for a very efficient simulation of the reduced system while retaining the correct fluctuations and behavior of the full system. This approach ought to be applicable to a wide range of genetic networks.

This article has been cited by other articles:

				M. R. Bennett, D. Volfson, L. Tsimring, and J. Hasty Transient Dynamics of Genetic Regulatory Networks Biophys. J., May 15, 2007; 92(10): 3501 - 3512. [Abstract] [Full Text] [PDF]

				J. Puchalka and A. M. Kierzek Bridging the Gap between Stochastic and Deterministic Regimes in the Kinetic Simulations of the Biochemical Reaction Networks Biophys. J., March 1, 2004; 86(3): 1357 - 1372. [Abstract] [Full Text] [PDF]