Architecture and Dynamics of Transcriptional Networks

The study of transcription regulation was initiated more than half a century ago, and has since then yielded a wealth of information on the regulation of gene expression. As transcriptional response was found to arise from a complicated set of interactions, system-level approaches became essential to their studies. Such approaches led to the presentation of transcription interactions in a network structure with consequence studies on the network topology. In particular, system-level studies led to the identification of a set of a recurring regulation patterns, called network motifs, that appear to serve as basic building blocks of transcription networks. In this chapter we will uncover the progress of the last few years in our understanding of the architecture of bacterial transcriptional networks, as well as functions provided by the network structure, focusing mainly on network motifs and their distinct dynamical properties. Because the transcriptional network of Escherichia coli, is the best studied network, most of the findings presented are from this bacterium. In many cases, however, they are applicable to other species as well.