Fig. 5. Expression of apterous, Dachshund and Eyes Absent in mutant backgrounds. Expression of ap (A-L) Dac (A-F) and Eya (G-L) in control and mutant late-stage-17 ap-clusters. In controls, expression of Dac is evident in three ap-cluster cells (A), being absent from the Tvb cell (see Fig. 3E,G). In ap mutants (ap^GAL4/ap^P44; UAS-nls-myc-EGFP^F/+), Dac is often de-repressed in the Tvb cell (B). In eya mutants (ap^GAL4, eya^Cli-IID/eya¹⁰; UAS-myc-EGFP^F/+), Dac is often lost from one cell (D), but not from the Tv cell (identified as the highest EGFP-expressing cell). In wit mutants (ap^GAL4/+; wit^A12, UAS-myc-EGFP^F/wit^B11), Dac expression is normal (E). In sqz mutants (ap^GAL4/+; sqz^Df, UAS-myc-EGFP^F/sqz^ie), expression of Dac is typically lost from one additional cell per ap-cluster (F), but not from the Tv cell (again, identified as the highest EGFP-expressing cell). Eya expression is not affected in any of the mutant backgrounds (G-L). As expected, expression of Dac and Eya is absent in dac (C; dac⁴, ap^GAL4/dac³; UAS-myc-EGFP^F/+) and eya (J; ap^GAL4, eya^Cli-IID/eya¹⁰; UAS-myc-EGFP^F/+) mutants, respectively.