title: Regulatory network reconstruction using an integral additive model with flexible kernel functions.
abstract: BACKGROUND
  Reconstruction of regulatory networks is one of the most challenging tasks of systems biology. A limited amount of experimental data and little prior knowledge make the problem difficult to solve. Although models that are currently used for inferring regulatory networks are sometimes able to make useful predictions about the structures and mechanisms of molecular interactions, there is still a strong demand to develop increasingly universal and accurate approaches for network reconstruction.
  
  
  RESULTS
  The additive regulation model is represented by a set of differential equations and is frequently used for network inference from time series data. Here we generalize this model by converting differential equations into integral equations with adjustable kernel functions. These kernel functions can be selected based on prior knowledge or defined through iterative improvement in data analysis. This makes the integral model very flexible and thus capable of covering a broad range of biological systems more adequately and specifically than previous models.
  
  
  CONCLUSIONS
  We reconstructed network structures from artificial and real experimental data using differential and integral inference models. The artificial data were simulated using mathematical models implemented in JDesigner. The real data were publicly available yeast cell cycle microarray time series. The integral model outperformed the differential one for all cases. In the integral model, we tested the zero-degree polynomial and single exponential kernels. Further improvements could be expected if the kernel were selected more specifically depending on the system.
authors.affiliation: Service Bioinformatique, Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France. Eugene.Novikov@curie.fr
authors.forename: Eugene
authors.initials: E
authors.lastname: Novikov
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Barillot
mesh_terms: D000465:Algorithms; D008962:Models, Theoretical; D049490:Systems Biology