title: Simple, realistic models of complex biological processes: positive feedback and bistability in a cell fate switch and a cell cycle oscillator.
abstract: Here we review some of our work over the last decade on Xenopus oocyte maturation, a cell fate switch, and the Xenopus embryonic cell cycle, a highly dynamical process. Our approach has been to start with wiring diagrams for the regulatory networks that underpin the processes; carry out quantitative experiments to describe the response functions for individual legs of the networks; and then construct simple analytical models based on chemical kinetic theory and the graphical rate-balance formalism. These studies support the view that the all-or-none, irreversible nature of oocyte maturation arises from a saddle-node bifurcation in the regulatory system that drives the process, and that the clock-like oscillations of the embryo are built upon a hysteretic switch with two saddle-node bifurcations. We believe that this type of reductionistic systems biology holds great promise for understanding complicated biochemical processes in simpler terms.
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA. james.ferrell@stanford.edu
authors.forename: James E
authors.initials: JE
authors.lastname: Ferrell
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Pomerening
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Nikki B
authors.initials: NB
authors.lastname: Trunnell
authors.forename: Wen
authors.initials: W
authors.lastname: Xiong
authors.forename: Chi-Ying Frederick
authors.initials: CY
authors.lastname: Huang
authors.forename: Eric M
authors.initials: EM
authors.lastname: Machleder
mesh_terms: D000818:Animals; D016203:CDC2 Protein Kinase / Q000096:biosynthesis; D004625:Embryo, Nonmammalian; D004789:Enzyme Activation; D025461:Feedback, Physiological; D016193:G1 Phase; D053858:Metabolic Networks and Pathways; D023421:Models, Animal; D009865:Oocytes / Q000502:physiology*; D014982:Xenopus laevis
chemical_list: D016203:CDC2 Protein Kinase