Emergence of switch-like behavior in a large family of simple biochemical networks

Dan Siegal-Gaskins
Mathematical Biosciences Institute (MBI), The Ohio State University

(May 20, 2010 11:30 AM - 12:18 PM)

Emergence of switch-like behavior in a large family of simple biochemical networks

Abstract

The variety of possible gene regulatory network topologies that exist for even a small number of network components is exceedingly large; for example, in systems consisting of two transcription factor-coding genes and their associated proteins, and considering only the most vital elementary biochemical processes, there exists over 40,000 possible networks (as defined by functionally unique sets of reactions). Understanding the dynamical behavior and stability of large classes of biological networks such as these remains a difficult problem, made particularly important as a result of the role played by network bistability in cellular differentiation, cell cycle control, viral reproduction, and other essential biological functions. To begin to address this challenge, we conduct a comprehensive survey of all two-component networks using the parameter-free Chemical Reaction Network Theory and find that ~45% (>18,000) have the capacity for bistability for some set of parameter values, including eight networks lacking the cooperativity typically found in bistable systems. These results illustrate the surprising ease with which switch-like behavior can arise in even simple biochemical networks, suggesting a large number of previously unknown bistable network topologies and the potential for novel synthetic gene circuit designs.