Pairs of PWMs that co-occur significantly in promoters of genes regulated in a cell cycle manner. We examined whether the nine PWMs reported in Tables 1 T2 T3 can be organized into regulatory modules. For each possible pair formed by these PWMs, we tested whether the prevalence of cell-cycle-regulated promoters that contain hits for both PWMs is significantly higher than would be expected if the PWMs occurred independently. Eight significant pairs were identified, each connected by an edge. The corresponding p-value is indicated next to the edge. The edge connecting the E2F–NRF1 pair is dashed to indicate that its significance is borderline.
