Figure 1.

Centrosomes and the SAC cooperate to promote neural stem cell viability and brain size. (A–D) Apoptosis (cleaved Casp3) was not observed in WT (A), mad2 (B), or sas-4 single mutant brains (C), but mad2 sas-4 double mutants displayed increased apoptosis (D). Arrows indicate apoptotic cells. (E and F) Samples were quantified per brain hemisphere (E) or standardized to brain size (F). (G–J) Third instar brains of indicated genotypes stained for actin (red) and α-tubulin (green). Note the smaller brains in mad2 sas-4 double mutants as well as reduced optic lobes (see Fig. 2). (K) Brain size quantification. Both mad2 sas-4 and mad1/Df;sas-4 double mutant brains were significantly smaller than WT or the respective single mutants. mad2 and mad1 single mutant brains were also slightly smaller than WT or sas-4 brains. Error bars represent means ± SD.