Enhanced frequency of putative binding sites in pheromone-induced genes. The bar diagram shows the frequency of genes containing putative Ste11 sites in pheromone-induced genes (closed bars) compared to the remaining genes in the genome (open bars). The number of genes in each set is shown in parenthesis. Perfect matches to a Ste11-binding-site matrix (see Materials and Methods) were counted at different intervals within the inter-genic regions (IGR) upstream of the initiation codon. The group of pheromone-induced genes contains the genes studied in Figure 2 that were induced by either M-factor and/or P-factor. The group of "remaining genes" was created by subtracting the pheromone-induced genes from the list of all S. pombe genes.