FIGURE 1 Results of an electrophoretic mobility shift assay demonstrate the shift in migration of Lac operator DNA (lane 1) with increasing concentrations of Lac repressor protein (lanes 2 through 7). The nondenaturing polyacrylamide gel preserves the Lac repressor in its folded state so that it can interact with the operator. The gel was stained with fluorophores that bind DNA (green) and protein (red). Yellow bands indicate protein-