A mathematical model of the regulation of the G1 phase of Rb+/+ and Rb−/− mouse embryonic fibroblasts and an osteosarcoma cell line

• Published in: Cell proliferation 1997-03, Vol.30 (3), p.171-194, Article 171
• Main Authors: Obeyesekere, M. N., Knudsen, E. S., Wang, J. Y. J., Zimmerman, S. O.
• Format: Article
• Language: English
• Subjects: Animals; Carrier Proteins; CDC2-CDC28 Kinases; Cell Cycle Proteins; Computer Simulation; Cyclin D; Cyclin E - metabolism; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinases - metabolism; Cyclins - metabolism; DNA-Binding Proteins; E2F Transcription Factors; Embryo, Mammalian - cytology; Fibroblasts - cytology; G1 Phase - physiology; Mice; Mice, Mutant Strains; Models, Theoretical; Original Paper; Osteosarcoma; Protein-Serine-Threonine Kinases - metabolism; Proto-Oncogene Proteins; Retinoblastoma Protein - deficiency; Retinoblastoma Protein - genetics; Retinoblastoma-Binding Protein 1; Transcription Factor DP1; Transcription Factors - metabolism; Tumor Cells, Cultured
• ISSN: 0960-7722; 1365-2184
• DOI: 10.1046/j.1365-2184.1997.00078.x

A mathematical model integrating the roles of cyclin D, cdk4, cyclin E, cdk2, E2F and RB in control of the G1 phase of the cell cycle is described. Experimental results described with murine embryo fibroblasts (MEFs), either Rb+/+ or Rb−/−, and with the RB‐deficient osteosarcoma cell line, Saos‐2, served as the basis for the formulation of this mathematical model. A model employing the known interactions of these six proteins does not reproduce the experimental observations described in the MEFs. The appropriate modelling of G1 requires the inclusion of a sensing mechanism which adjusts the activity of cyclin E/cdk2 in response to both RB concentration and growth factors. Incorporation of this sensing mechanism into the model allows it to reproduce most of the experimental results observed in Saos‐2 cells, Rb−/− MEFS, and Rb+/+ MEFs. The model also makes specific predictions which have not been tested experimentally.