Statistical analysis of the spatial distribution of operons in the transcriptional regulation network of Escherichia coli

Abstract

We have performed a statistical analysis of the spatial distribution of operons in the transcriptional regulation network of Escherichia coli. The analysis reveals that operons that regulate each other and operons that are coregulated tend to lie next to each other on the genome. Moreover, these pairs of operons tend to be transcribed in diverging directions. This spatial arrangement of operons allows the upstream regulatory regions to interfere with each other. This affords additional regulatory control, as illustrated by a mean-field analysis of a feed-forward loop. Our results suggest that regulatory control can provide a selection pressure that drives operons together in the course of evolution.