Figure 2: Apoptosis is not the cause of Nbs loss in aneuploid brains.

(a) Schematic representation of L3 type I Nbs asymmetric divisions. The larger pink cell represents one Nb that asymmetrically segregates polarity cues and cell fate determinants. Spindle positioning along the polarity axis generates two daughter cells of unequal fate and size. The larger self-renewing cell, inherits the apical Par complex and Insc/Pins/Mud/Gαi complexes and maintains Nb identity whereas the small green daughter cell (the GMC) receives Numb, Pros and Brat, which promote differentiation and suppress self-renewal. The GMC divides once more to generate two terminally differentiated neurons or glial cells (purple cells). (b) Pictures of WT, SakOE,mad2 and bub3 L3 brain lobes stained for Deadpan (Dpn) a Nb marker. Aneuploid brains show a reduced number of Nbs in the CB region, highlighted by the yellow dashed line. Scale bar, 50μm. (c) Dot plot chart showing the quantification of Nbs number (Dpn⁺ cells) in WT (red dots, n=14 lobes), SakOE,mad2 (green dots, n=17 lobes) and bub3 (blue dots, n=32 lobes) CBs. Each dot represents a brain lobe. The line represents the mean and the error bars the s.d. Statistical significance (SS) was assessed by an unpaired t-test. ****(P<0.0001). (d) Pictures of WT, SakOE,mad2, bub3 and p35,bub3 L3 brain lobes stained with antibodies against cleaved caspase 3 (CC3, shown in red). DNA is shown in blue. The yellow dashed line marks the CB region. Scale bar, 50 μm. (e) Dot plot chart showing the quantification of the ratio between CC3 positive cells per CB area in WT (red dots), SakOE,mad2 (green dots), bub3 (blue dots) and p35, bub3 (blue circles) brains. Each dot represents the rate measured in each brain lobe. The line represents the mean and the error bars the s.d. SS**** was assessed by an unpaired t-test. **(P=0.005). (f) Dot plot chart showing the quantification of Nbs number in bub3 (full blue circles) and p35,bub3 brain lobes (empty blue circles) where apoptosis has been inhibited. The line represents the mean and the error bars the s.d. SS was assessed by an unpaired t-test.