Figure 5
dPax2 effects Delta/Notch signaling. (A-F) Eye imaginal discs from control (A,C), spapolmutants (B,C), mirr>GFP (E), and mirr>GFP,dPax2RNAi were immunostained for Delta (A,B, green), E-cadherin (A,B, blue), LacZ (C,D, green), Pros (C,D, magenta), GFP (E,F, green), or E(spl) (E,F, magenta). All discs are oriented with anterior left. In wild-type discs, Delta expression is high in the first four rows of ommatidia after the morphogenetic furrow (MF) and then decreases thereafter (A). In spapolmutants, however, Delta is up-regulated again by row 7. Delta-LacZ expression in wild-type discs is down-regulated at the more posterior rows of the disc and do not co-localize with Pros in CC precursors (C), whereas in spapol mutants, Delta-LacZ expression is maintained at high levels throughout the disc and co-localizes with Pros in the most posterior rows (D), indicating that dPax2 transcriptionally represses Delta expression in CC precursors. E(spl) (E,F) is equally expressed when a UAS-GFP transgene is misexpressed in the dorsal half of the eye imaginal disc with mirr-GAL4 (E), but is significantly reduced where UAS-dPax2RNAi/UAS-GFP are co-expressed (F), revealing that dPax2 is important for maintaining high Notch activity.