Figure 3

Enhancer-blocking assay using a dual-reporter transgene. Reporter expression in S2 cells transfected with a single 2xR dual reporter transgene. A. A diagram of the 2xR dualreporter transgene vector. B. Top: RFP and GFP expression ofS2 cell containing 2xR before (top) and after (middle) induction. Bottom: FACS chart of 2xR-transfected S2 cells before (left) andafter (right panel) induction. C. Top: a diagram of 2xR transgene with a test insulator (In, red oval) inserted between MTand the eve-GFP reporter. Bottom: FACS chart of induced S2 cells containing 2xR-spacer (left) and 2xR-SF1 (right). Insets containing double positive cells are shown at identical position. D. Ratio (R) between GFP and RFP induction in S2 cells containing 2xR-suHw, SF1, SF1b, Fab7, and Fab8, respectively. Number of replicates for each experiment is shown in parentheses. Standard error of mean (SEM) is indicated.