Analysis of cortical F-actin and cell shape in hts^null mutant PECs. (A–B’) A Triton X-100–permeabilized pupal eye disc containing GFP-positive hts^null MARCM clones was stained for phalloidin. A and A’ and B and B’ show z-projections at apical and lateral position, respectively. Note the reduced cortical F-actin level in hts^null mutant PECs in both apical and lateral membrane compared with wild-type PECs. Quantification of phalloidin membrane intensity is shown in E. (C–D’) Pupal eye discs containing GFP-negative hts^null mutant clones (C and C') or GFP-positive hts^null MARCM clones (D and D') were stained for DE-cad (red, in C and C’) or Dlg (red, in D and D’). hts^null mutant PECs (arrowhead in C) have similar apical size as wild-type PECs (arrow in C) but exhibit increased lateral size (arrowheads in D) compared with wild-type PECs (arrows in D). Quantification of ommatidium apical and lateral size is shown in F. (E) Mean phalloidin membrane intensity of hts^null mutant PECs at the indicated apical-basal position analyzed in A–B. Note the decrease of phalloidin membrane intensity in both apical and lateral domains. Data are means ± SEM (n ≥ 20 cells, representative of five animals). ****, P < 0.0001. (F) Normalized mean ommatidium apical and lateral size analyzed in C–D. Data are means ± SEM (n ≥ 15 ommatidia, representative of five animals). ****, P < 0.0001. N.S., no significance. (G) Normalized mean apical membrane phalloidin intensity in PECs of the indicated genotypes. Note the higher apical cortex F-actin level in hts^null mutant PECs compared with α-spec RNAi PECs. ****, P < 0.0001. Scale bar, 5 µm.