Fig. 3. Aberrant IPC morphogenesis and unstable IPC-IPC junctions in retinas with reduced Dpp signaling. (A-D) In vivo imaging of a Drosophila retina with reduced Tkv activity [GMR-gal4/+; UAS-Catenin-GFP/tkv⁸; UAS-tkv-IR1(2x)/UAS-tkv-IR1(2X)] (see also Movie 2 in the supplementary material). Hours APF are indicated. Pseudo colored in green are examples of IPCs that transiently lose their apical contact and leave primary pigment cells from adjacent ommatidia (asterisks) in direct, aberrant contact. Arrows point to examples of adherens junctions, which disappear as the IPC-IPC surface contact decreases. (E-J) Clones of tkv⁴ (E-H) and Mad¹² (I,J) dissected at 25 hours APF and stained with anti-DE-cadherin (red; E-J). Clonal tissue is marked by the absence of GFP (green; F,H,J) or outlined by dotted lines (E,G,I). Arrows point to IPC-IPC junctions with abnormally low-to-undetectable DE-cadherin staining.