Biological regulatory network inference Richard Bonneau, NYU We have recently described a network inference algorithm, the Inferelator, which infers regulatory influences for genes and/or gene clusters from mRNA and/or protein expression levels. The procedure can simultaneously model equilibrium and time-course expression levels, such that both kinetic and equilibrium expression levels may be predicted by the resulting models. Through the explicit inclusion of time, and gene-knockout information, the method is capable of learning causal relationships. It also includes a novel solution to the problem of encoding interactions between predictors. We discuss the results from an initial application of this method to the halophilic archaeon, Halobacterium NRC-1. We have found the network to be predictive of 130 newly collected microarray datasets and have also validated parts of the network using ChIP-chip. I'll go over the algorithm, the current bottlenecks and some new directions we hope to take to improve the stability of our networks over longer time scales. I'll also discuss methods for scaling up the work to multiple-species data-sets and multi-cellular organisms. http://genomebiology.com/2006/7/5/R36 http://www.biomedcentral.com/1471-2105/7/280 http://www.nature.com/msb/journal/v3/n1/full/msb4100118.html