Stability analysis of the GAL regulatory network in Saccharomyces cerevisiae and Kluyveromyces lactis

Background: In the yeast Saccharomyces cerevisiae, interactions between galactose, Gal3p, Gal80p, and Gal4p determine the transcriptional status of the genes required for the galactose utilization. Increase in the cellular galactose concentration causes the galactose molecules to bind onto Gal3p which, via Gal80p, activates Gal4p, which induces the GAL3 and GAL80 gene transcription. Recently, a linear time-invariant multi-input multi-output (MIMO) model of this GAL regulatory network has been proposed; the inputs being galactose and Gal4p, and the outputs being the active Gal4p and galactose utilization. Unfortunately, this model assumes the cell culture to be homogeneous, although it is not so in practice. We overcome this drawback by including more biochemical reactions, and derive a quadratic ordinary differential equation (ODE) based model. Results: We show that the model, referred to above, does not exhibit bistability. We establish sufficiency conditions for the domain of attrac...

• Type: Journal
• Year: 2010
• Where: BMCBI
• Authors: Vishwesh V. Kulkarni, Venkatesh Kareenhalli, Pushkar Malakar, Lucy Y. Pao, Michael G. Safonov, Ganesh A. Viswanathan
• Keywords: BMCBI 2010, Galactose, Model, Regulatory System