Abstract:

The interactions between protein, DNA and RNA in living cells constitute molecular networks that govern various cellular functions. These networks function very reliably despite the complex environment in and outside of the cell. To understand the origin of this robustness, we study the network regulating the cell division (cell cycle) of the budding yeast. With the use of simple dynamical models, we show that the cell-cycle network is extremely stable and robust for its function. The biological stationary state is a global attractor. The biological pathway is a globally attracting trajectory. These properties are largely preserved with respect to small perturbations to the network.  However, there are "weak" points in the network and certain perturbations lead to abnormal behavior which may have implications to disease.