Fig. 4.

The FCs nonautonomously contribute to NC death events. (A–D’) Stage 13 egg chambers stained with DAPI (blue) and TUNEL (green) as a marker for DNA fragmentation. (Scale bar, 50 μm.) (A and A’) Control (nanos-GAL4/+) egg chamber contains several TUNEL-positive NC nuclei (arrow), although only one nucleus is visible by DAPI staining. (B and B’) Overexpression of Diap1 (nanos-GAL4/UAS-Diap1) shows several TUNEL-positive nuclei (arrow). (C and C’) Control (PG150-GAL4/+; UAS-luciferase^RNAi/+) egg chamber has many TUNEL-positive NC nuclei (arrow). (D and D’) The knockdown of draper specifically in the stretch FCs (PG150-GAL4/+; UAS-draper^RNAi/+) shows no TUNEL staining. (E) The percentage of egg chambers containing TUNEL-positive nuclei in the late stages of oogenesis (stages 11–13) was quantified for each genotype. (F–I’) Egg chambers expressing the BB127 lacZ enhancer trap are stained with DAPI (blue) and α–β-Gal antibody (red) to detect nuclear leakage. BB127 labels both NCs (large nuclei) and centripetal FCs (small nuclei). (F–G’) Control egg chambers (mixed siblings, BB127/+; Sco or UAS-draper^RNAi/CyO or UAS-GAL4; +/MKRS) have NC nuclear β-Gal in stage 10B (F and F’) and cytoplasmic β-gal in stage 11 (G and G’). (H–I’) draper Ced-12 double knockdowns (BB127/+; UAS-draper^RNAi/CyO or UAS-GAL4; +/GR1-GAL4 UAS-Ced-12^RNAi) have nuclear β-Gal in stage 10B (H and H’). In this stage 11 egg chamber, β-Gal staining is still largely nuclear (arrows, I and I’). (J) The average number of intact NC nuclei in stage 11 egg chambers was quantified. Data presented are mean ± SEM. *P < 0.05, **P ≤ 0.01. (K–N) Stage 14 egg chambers stained with DAPI (cyan) and Lamin Dm₀ ADL67.10 antibody (red). (K and L) Control egg chambers are devoid of NC nuclei, and Lamin staining appears at the periphery of remaining FC nuclei (L, arrowhead). (M and N) draper^∆5 mutant egg chambers have Lamin associated with persisting NC nuclei (N, arrow) in addition to labeling FC nuclei (N, arrowhead).