Fig. 7. Overexpression of sim causes the premature incorporation of lamina neurons into the assembling domain. (A-C) Overexpression of sim in lamina neurons using NP6099-GAL4 (B,C). Lamina neurons are marked by Dac (magenta) and R axons are visualized by anti-HRP (white in A,B). NP6099-GAL4 driving GFP alone was used as a control (A). 3D reconstruction of Dac expression in B is shown in C. The number of lamina neurons in the pre-assembling domain is reduced (arrowheads in A-C). (D-I) Horizontal views of wild-type and mutant lamina at third larval instar. In contrast to wild type (D,G) and sim mutants (F,I), lamina neurons overexpressing sim (E,H) do not migrate apically; instead, they enter the assembling domain directly (arrowheads in D-F; yellow broken lines in G-I). The lamina precursor cells at the lamina furrow are visualized with tkv-lacZ (magenta). Lamina neurons are marked by NP6099-GAL4 UAS-nlsGFP (blue in D) or Dac (blue in E,F), and R axons by anti-HRP (white). G-I are single channel of tkv-lacZ for D-F, respectively. The migratory route is shown by arrows.