Fig. 1

Loss of chro function resulted in NSCs quiescence in larval brains. a Schematic illustration of timing of reactivation in wild-type larval brain NSCs. b Third-instar larval brains in control, chro RNAi knockdown and chro ⁻ NSCs were labelled with Mira, Dpn and EdU. The right panels are enlarged views of the yellow boxes in the left panels. chro ⁻ is a trans-heterozygous mutant between chro ⁷¹, an N-terminal 71 amino acids truncation, and chro ⁶¹², a truncated Chro retaining its N-terminal 612 amino acids. c Quantification of percentages of Dpn⁺ EdU⁺ cells in various genotypes. d PH3 and Mira were labelled in control, chro RNAi knockdown and chro ⁻ mutant. e Quantification of numbers of PH3⁺ Mira⁺ cells in control (23 ± 4, n = 22) and chro ⁻ (6 ± 2, n = 21) larval brains. f Mira and Dpn were labelled in control, chro ⁶¹²/Df(3L)ED231(chro ^612/Df), chro ^17a/71 and chro ^8c/71 NSCs. g Dpn and EdU were labelled for control, chro ^612/Df and chro ^17a/71 larval brains. h BAC clone CH322-159M1 containing genomic DNA encompassing wild-type chro and its promoter region (Chro^159M1) was introduced into chro ⁻ or chro ^612/Df mutant background. Dpn and EdU were labelled in chro ⁻, Chro^159M1; chro ⁻, chro ^612/Df and Chro^159M1; chro ^612/Df larval brains. i Dpn and EdU were labelled in the VNC of control, chro RNAi knockdown and chro ⁻ mutant. j Control, chro RNAi and chro ⁻ mutant VNCs were labelled with Mira. Insets are enlarged view of the white dotted boxes. k Quantification of the diameter of third-instar larval NSCs in control, chro RNAi and chro ⁻ mutant. NSC diameter: control, 10.7 ± 0.1 µm; n = 102; chro RNAi, 11.0 ± 0.1 µm; n = 101 and chro ⁻ mutant, 11.0 ± 0.1 µm; n = 103. l Mira and Chro were stained in wild-type larval brains at 8 h ALH. The right panel is enlarged view of the yellow box in the left panel. Yellow arrow indicates wild-type quiescent NSC. All error bars indicate ± SD. in c, e and k. *** indicates P < 0.001 in c by Student’s t-test. The central brain is to the left of the white dotted line in b, d, g, h. Arrows indicated NSCs and arrowheads indicated the cellular extension of NSCs in b, f and j. Scale bars, 10 µm