Fig. 2

Apical area dynamics in NSCs. (A) 3D dorsal view of the pallial surface in a 2.5-mpf casper;Tg(deltaA:eGFP);Tg(gfap:hZO1-mKate2) fish imaged intravitally using biphoton multicolor microscopy. deltaA:eGFP: deltaA transcription, cyan; gfap:ZO1-mKate2: NSC apical contours, yellow. Arrows show the anteroposterior (A-P) and mediolateral (M-L) axes. Scale bar, 30 μm. (B) Schematic example of a dividing track (horizontal tree) (horizontal arrow: time; vertical bars: imaging tp, consecutive tps separated by 2 to 3 days), to position a mother NSC (MC, blue arrow, example picture), daughter NSCs (DCs, cytokinesis event, green arrow), and DC+1 at the next tp (pink arrow, example picture). DC is the first tp where two daughters can be identified. We only scored dividing tracks where MC was preceded by at least 4 to 5 days without division (black part of time arrow). Track interruption before the end of the recording period corresponds to a delamination (example in orange). Scale bars, 10 μm. (C) 3D maximum projection with split and merged channels of the first tp of a time lapse. Color code for the overlay of middle image: NSCs that will divide (purple, tp of division), cells that will delaminate (orange, tp of delamination). The apparent spreading of deltaA:GFP (magenta) into neighboring cells results from their body ballooning beyond their apical surface (movie S1). (D) AA distribution of all MCs and all their DCs. Red dashed line: median (n = 4 independent hemispheres, Dm), 102 μm2 for MCs and 45 μm2 for DCs (P < 0.0001, Mann-Whitney). (E) Normalized AA of qNSCs during nondivision phases relative to time and deltaA expression (deltaAneg NSCs: gray, deltaApos NSCs: blue) (with median and 95% CI). (F) Normalized area of the entire region of interest (ROI) over time (green) versus normalized AA of deltaAneg qNSCs during nondivision phases [gray, as in (E)] (with median and 95% CI).