title: Analysis of a minimal model for p53 oscillations.
abstract: Oscillatory behaviours in genetic networks are important examples for studying the principles underlying the dynamics of cellular regulation. Recently the team of Alon has reported a surprisingly rich oscillatory response of the p53 tumor suppressor to irradiation stress et al. [Lahav, G., Rosenfeld, N., Sigal, A., Geva-Zatorsky, N., Levine, A.J., Elowitz, M.B., Alon, U., 2004. Dynamics of the p53-Mdm2 feedback loop in individual cells. Nat. Genet. 36 (2), 147-150; Geva-Zatorsky, N., Rosenfeld, N., Itzkovitz, S., Milo, R., Sigal, A., Dekel, E., Yarnitzky, T., Liron, Y., Polak, P., Lahav, G., Alon, U., 2006. Oscillations and variability in the p53 system. Mol. Syst. Biol. 2, 2006.0033]. Several models for this system have been proposed by different groups, based essentially on negative feedback loops. In this paper we investigate in detail oscillations and stability in a deterministic time delayed differential model of the core circuit for p53 expression. This model is representative of a class of modelling approaches of this system, based on a "minimal" set of well-established biomolecular regulations. Depending on the protein degradation rates we show the existence of bifurcations between a stable steady state and oscillations both in presence and absence of stress.
authors.affiliation: Laboratoire Matières et Systèmes Complexes, Université Paris 7, CNRS UMR 7057, c.c. 7056, 75205 Paris Cedex 13, France. samuel.bottani@univ-paris-diderot.fr
authors.forename: Samuel
authors.initials: S
authors.lastname: Bottani
authors.forename: Basile
authors.initials: B
authors.lastname: Grammaticos
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology* / Q000528:radiation effects; D004249:DNA Damage; D025461:Feedback, Physiological / Q000502:physiology / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000502:physiology / Q000528:radiation effects; D053263:Gene Regulatory Networks / Q000502:physiology* / Q000528:radiation effects; D016158:Genes, p53 / Q000502:physiology* / Q000528:radiation effects; D008957:Models, Genetic; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D016159:Tumor Suppressor Protein p53