Figure 1.

Dup overexpression causes rereplication in mitotic cycling and endocycling cells, but only mitotic cycling cells apoptose. (A,B) Stage 5 mitotic cycling follicle cell nuclei labeled with TOTO-3 (blue) and BrdU (red) from wild type (A) or hsp70:Myc:FL-Dup overexpressing (B) females. Nuclei of hsp70:Myc:FL-Dup overexpressing follicle cells were enlarged or pycnotic (arrowheads). (C,D) Stage 8 endocycling follicle cells from wildtype (C) or hsp70:Myc:FL-Dup overexpressing (D) females. hsp70:dup overexpression in endocycle follicle cells resulted in enlarged, but not pycnotic, nuclei. (E,F) Dup overexpression activated caspase-3 (green in E) and TUNEL labeling (green in F) in mitotic follicle cells before stage 7 of oogenesis, but not in endocycling follicle cells of later egg chambers, DNA (red). The germarium (gm) and select stages of oogenesis are indicated by numbers. (G) Percent of ovarioles that had five or more pycnotic nuclei in mitotic follicle cells (M) or one or more pycnotic nuclei in endocycle follicle cells (E) from hsp70:Myc:FL-Dup ovaries either without induction or 7 h after one heat treatment (n ≥ 65 ovarioles). (H) Percent of caspase-positive follicle cells from stages 1–5 (M) and stages 9–10 (E) from hsp70:Myc:FL-Dup females without induction or after three heat inductions over 30 h. Cells were counted in a total of 25 ovarioles for each sample. (M vs. E) Heat shock: P < 10⁻⁸. Total cells counted: mitotic, n > 10,000; endocycle, n > 5000. Bars: A–D, 5 μm; E,F, 50 μm.