Testing the enhancer-blocking activity of Pita binding sites at the MCP insulator. Reductive schemes of transgenic constructs used to examine the enhancer-blocking activity of Pita binding sites at the MCP element. This element is shown as a black box with a white pentagon (dCTCF binding site) and a white or a black oval indicating wild-type (A) or mutated (B) Pita binding sites. Figures in the columns show the numbers of transgenic lines with different levels of pigmentation in the abdominal structures. Histograms show binding of dCTCF, Pita, and CP190 proteins to MCP with wild-type (A) or mutated (B) Pita binding sites in the transgenic construct. For other designations, see Figure 6.