Figure 5.

Larval brains of bub1 mutants contain many apoptotic nuclei. bub1 mutant (A–C) and wild-type (Oregon-R; D–F) brains were labeled by a TUNEL-based assay (A and D) for the presence of apoptotic nuclei, and stained with propidium iodide for DNA (B and E); a merged view with DNA in red and the TUNEL signal in green is shown in C and F. Many apoptotic nuclei are seen in bub1 mutant brains but not in wild-type; the majority of these TUNEL-positive nuclei are also pycnotic as seen by the abnormally condensed DNA signal. G–I show bub1 mutant larval brains stained with annexin V to reveal phosphatidylserine on the outside of the cell membrane (G), propidium iodide (H), and a merged view (I) with DNA staining in red and the annexin V signal in green. No annexin V staining is observed within wild-type brains (not shown). Bars: (A) 10 μm; (G) 5 μm. A–F are at the same magnification, as are G–I.