Figure 3.

Functional activity of selected terminators in the eyes. Testing the enhancer-blocking activity (A) of the terminator found in the regulatory region of the Achaete–Scute gene complex (T^ASC) and (B) of the SV40 terminator (T^SV40). A terminator (T) is shown as a black hexagon; in construct names, terminators are indicated in superscript. The eye enhancer is represented by the rectangle marked ‘Ee’. The Wari insulator is shown as a gray oval marked ‘wari’. Downward arrows indicate cleavage sites for Cre or FLP recombinase. Testing the activity of (C) T^ASC and (D) T^SV40 terminators in the eyes. ‘+GAL4’ indicates that eye phenotypes in transgenic lines were examined after induction of GAL4 expression. In this case, N is the number of lines in which flies acquired a new w phenotype upon induction of GAL4. For other designations, see Figures 1 and 2.