Msps suppresses NB overgrowth and regulates asymmetric division. (A) A schematic diagram of msps mutation in msps^P18. (B) Larval brains of control, msps^P18, msps^P18/P, and msps^P18 with full-length Msps (Msps-FL) overexpression labeled for Dpn. (C) Quantification of the number of central brain NBs per brain hemisphere (with SD) for (B). Control: 98.7 ± 6.9 (n = 21); msps^P18: 296.5 ± 49.9 (n = 26); msps^P18/P: 303.3 ± 47.3 (n = 26); Msps-FL overexpression in msps^P18: 97.4 ± 6.8 (n = 20). ***, P < 0.001. (D and E) Control (FRT82B) and msps^P18 type I (D) and type II (E) NB clones labeled for Dpn, Ase and CD8. The white dotted lines label the outline of the NB lineages. Arrows indicate the NBs. (F) Metaphase NBs of control, msps^P18, msps^P18/P, and msps^P18 with Msps-FL overexpression labeled with Insc, α-tubulin, and DNA. (G) aPKC and DNA in control and msps^P18 metaphase NBs. (H) aPKC, phalloidin, PH3, and DNA in control and msps^P18 anaphase and telophase NBs. Bars: (B) 20 µm; (D–H) 5 µm.