Fig. 3. Eye/antennal imaginal disc expression from opa Lac-Z constructs. (A) Schematic diagram of the opa gene. Stippled boxes represent exons and thin lines represent introns. Positions of five opa constructs are indicated below the gene diagram. Position of the opa^3D246 enhancer trap is indicated by the triangle. (B-D) ß-galactosidase expression from (B) opa02 lacZ, (C) opa03 lacZ and (D) opa04 lacZ, as detected by histochemistry. Lateral peripodial staining in B-D is indicated by arrowheads, and staining of the disc proper ring in D by an arrow. Note that B-D comprises the entire pattern seen in the opa enhancer trap opa^3D246 shown in Fig. 2B.