Figure 1: Characterization of aneuploid brains.
From: Aneuploidy causes premature differentiation of neural and intestinal stem cells
(a) Phalloidin staining of wild-type (WT) (left) and SakOE,mad2 (right) brain lobes. In the WT lobe both the CB, highlighted by the yellow dashed line, and optic lobe (OL), highlighted by the red dashed line appear highly organized, while SakOE,mad2 lobes appear smaller and disorganized. Scale bar, 50 μm. (b–g) Stills of time-lapse movies of mitotic neuroblasts (Nbs) expressing Histone 2B-RFP and Tubulin-GFP, in red and in green, respectively. (b) Wild-type Nb with two centrosomes forms a bipolar spindle and divides asymmetrically to give rise to two cells. (c) SakOE Nb with at least five centrosomes that form a bipolar spindle due to centrosome clustering and inactivation generating two daughter cells. (d) SakOE,mad2 Nb with at least ten centrosomes and increased chromosome number. Not all centrosomes cluster and the cell undergoes a tripolar division. (e) SakOE,mad2 Nb with increased chromosome number and at least 15 centrosomes that cluster to form a bipolar spindle. Lagging chromosomes are noticed during anaphase. (f) SakOE,mad2 Nb divides in a bipolar way, but presents defects in cytokinesis. (g ) SakOE, bubR1* (bubR1ΔKEN in bubR1 mutant background) Nb divides in a bipolar way but shows extra lagging chromatids during anaphase. Scale bar, 3 μm. (h) Graph bars showing the quantification of mitotic defects in WT (n=110), SakOE,mad2 (n=166) and SakOE, bubR1* (n=64) Nbs, considering spindle morphology (left), chromosome segregation defects (middle) and cytokinesis defects (right). Statistical significance (SS) was determined using Fisher’s exact test. ns, not significant, ***(P<0.0001), **(P=0.0061). (i) Fluorescent in situ hybridization with chromosomes II and III probes (green and red) in WT, SakOE, and SakOE,mad2 Nbs. Scale bar, 2 μm. (j) Graph bars showing the quantification of FISH in WT (n=227 cells), mad2 (n=166 cells), SakOE (n=153 cells) and SakOE,mad2 (n=109 cells) brains. (k) Dot plot chart showing the time spent in mitosis measured as the time elapsed between nuclear envelope breakdown and anaphase onset. Each dot represents a cell. Time is in minutes and the line represents the mean and the error bars the s.d. Statistical significance was assessed by unpaired t-test. *(0.01<P<0.05), **(0.001<P<0.01) and ***(P<0.001).
