Cells with Hh-activated Patched receptor synthesize the Wingless protein (red in Figure 4). If a "Drosophila" embryo is altered so as to produce Hh in all cells, all of the competent cells respond and form a broader band of Wingless-expressing cells in each segment. The "wingless" gene has an upstream transcription regulatory region that binds the Ci transcription factor in a Hh-dependent fashion resulting in an increase in "wingless" transcription (interaction 2 in Figure 3) in a stripe of cells adjacent to the stripe of Hh-producing cells.