Figure 3.

Ommatidia rescued by ato or scute exhibit different structure and developmental processes. (A, C, and E) ato¹ mutant expressing ato (UAS-ato/+; GAL4–7,ato¹/ato¹ ). (B, D, and F) ato¹ mutant expressing scute (UAS-sc,ato¹/GAL4–7,ato¹). (A and B) Tangential sections of compound eyes. (A) Ommatidia in ato-rescued eye often contain more than eight photoreceptors. Multiple R8-like cells (arrow in A) in one ommatidium frequently are seen. (B) Most ommatidia in scute-rescued eye have only outer photoreceptors, and the number is lower than normal. (C–F) Eye discs from third instar larva (C and D) or early pupae (E and F) stained with an anti-Boss antibody. Third instar larval discs of scute rescued ato¹ mutant (D) express no detectable Boss protein, although the MF has clearly advanced (arrowhead in D). Boss is detected only in early pupal discs of ato¹ mutant expressing scute (F), in many fewer cells than those in the ato-rescued discs (E). (Magnifications: A and B, ×700; C–E, ×200.)