Outlines of the pathways studied. (a) Methionine (MET); (b) nitrogen catabolite repression (NCR); (c) pseudohypal growth/mating (HYPE); (d) regulation of early meiotic genes (CCYCLE); (e) pleiotropic drug resistance (PDR). The sub-networks enlarged from Figure 2, with the identified motifs within the pathway drawn from the interaction databases, are shown on the left (colors and conventions are the same as in Figure 2). A schematic representation of the regulation mechanisms for the same pathways, based on the present experimental knowledge as discussed in the text, is shown on the right. Full lines represent transcriptional regulation, dashed lines non-transcriptional regulation, and wavy lines transformations and syntheses. Arrowheads, positive regulation; lines ending in a terminal bar, negative regulation.