FIGURE 4

The loss of dAPP-BP1 causes apoptosis, not cell proliferation. (a–d) Third instar eye discs. Scale bar is 50 m. (a, b) TUNEL assay. White indicates TUNEL signals. (c, d) Immunostaining by anti-activated caspase 3. (Casp3=anti activated caspase 3). White indicates anti-activated caspase 3 positive site. (a) dAPP-BP1 ^Ex62 homozygote. The size of eye disc is greatly reduced and TUNEL signals are greatly increased compared with the w ¹¹¹⁸ wildtype eye disc (b). (c) dAPP-BP1 ^Ex62 homozygote. The level of activated caspase 3 is greatly increased in the wildtype, w ¹¹¹⁸ (d). Clones carrying dAPP-BP1 ^Ex62 are marked by the lack of GFP (e, g, k, m) or beta-galactosidase (h, j, k, m) expression. (e–g) The level of activated caspase is increased in dAPP-BP1 ^Ex62 clones in 3rd larvae eye disc (arrows). (h–j) The amount of activated caspase is increased in mutant clones in 3rd larvae wing disc (arrows). (k–m) PH3 is anti –phospho histone H3. dAPP-BP1 ^Ex62 cells retain the ability to proliferate. (n–p) Clones carrying dAPP-BP1 ^Ex62 are marked by the lack of myc expression. The number of elav-positive cells is decreased in dAPP-BP1 ^Ex62 clones (arrows) (q) dAPP-BP1 ^Ex183 homozygous clones and twin spots (white asterisk=dAPP-BP1 ^Ex183 clones (arrows) homozygous clones were marked by lack of -galactosidase expression. Black asterisk=twin spots. -galactosidase=Green). (r) Area measurements of 31 pairs of homozygous dAPP-BP1 ^Ex183 mutant and wild-type twin clones (scale: 100 pixels). Wild-type and mutant cells are produced in the same cell division, so differences in clone area reflect differences in growth or cell survival after clone induction. (s) dAPP-BP1 ^Ex62 homozygous clones and twin spots (white asterisk=dAPP-BP1 ^Ex62 homozygous clones were marked by lack of -galactosidase expression. Black asterisk=twin spots. -galactosidase=Green). (t) Area measurements of 42 pairs of homozygous dAPP-BP1 ^Ex62 mutant and wild-type twin spots (scale: 100 pixels). The area of wild-type twin clones is about three times larger than that of mutant clones