nstitute of Molecular Plant Sciences, University of Edinburgh
Defines light value depending on time of day LD is a function of time of the day, LD=1 at time t=0 (dawn) and changes to LD=1 at time t=12(dusk) and remains at that value until dawn when it resumes it cycle. The original publication made use of a combination of Function definition, rate rules and events to accomplish this while the the model here does the same thing without the use of Events. This makes it portable across simulators without compromising the published model in any way.
Locke2005 - Circadian Clock SBML model of the interlocked feedback loop network The model describes the circuit depicted in Fig. 4 and reproduces the simulations in Figure 5A and 5B. It provides initial conditions, parameter values and rules for the production rates of the following species: LHY mRNA (cLm), cytoplasmic LHY (cLc), nuclear LHY (cLn), TOC1 mRNA (cTm), cytoplasmic TOC1 (cTc), nuclear TOC1 (cTn),X mRNA (cXm), cytoplasmic X (cXc), nuclear X (cXn), Y mRNA (cYm), cytoplasmic Y (cYc), nuclear Y (cYn), nuclear P (cPn). This model was successfully tested on MathSBML and SBML ODE Solver. Fig 5B is not in the right phase. However, the data is correct relative to the light/dark bars at the top of the figure. This model is described in the article: Extension of a genetic network model by iterative experimentation and mathematical analysis. Locke JC, Southern MM, Kozma-Bognár L, Hibberd V, Brown PE, Turner MS, Millar AJ Molecular Systems Biology [2005; 1: 2005.0013] Abstract: Circadian clocks involve feedback loops that generate rhythmic expression of key genes. Molecular genetic studies in the higher plant Arabidopsis thaliana have revealed a complex clock network. The first part of the network to be identified, a transcriptional feedback loop comprising TIMING OF CAB EXPRESSION 1 (TOC1), LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), fails to account for significant experimental data. We develop an extended model that is based upon a wider range of data and accurately predicts additional experimental results. The model comprises interlocking feedback loops comparable to those identified experimentally in other circadian systems. We propose that each loop receives input signals from light, and that each loop includes a hypothetical component that had not been explicitly identified. Analysis of the model predicted the properties of these components, including an acute light induction at dawn that is rapidly repressed by LHY and CCA1. We found this unexpected regulation in RNA levels of the evening-expressed gene GIGANTEA (GI), supporting our proposed network and making GI a strong candidate for this component. This model is hosted on BioModels Database and identified by: BIOMD0000000055 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.