Fig. 7. Interactions among 52 genes in the transcriptional regulation network of S. cerevisiae. The gene names are arranged in such a way that left to right illustrates causality. The number of non-regulatory genes regulated by each column of regulatory genes is shown above. Bold type indicates self-activation, bold italics indicates self-inhibition, and borders indicate essential genes. Reproduced with permission from the Nature Publishing Group (http://www.nature.com/naturegenetics) (Guelzim et al., 2002).