Fig. 3

Post-embryonic her5-positive cells contribute to the generation of the posterior TeO via a TPZ intermediate. A-D. Adult fate of her5-positive cells assessed using Cre-lox recombination at the indicated stages (top schemes) and analysed in whole-mount brains (panels 1, dorsal views, anterior left, dotted line to surround the TeO) or on horizontal sections (panels 2 and 3, confocal views, with high magnifications of boxed areas in panels 3). The anterior limit of the TeO domain issued from recombined cells is indicated by yellow arrowheads in panels 1 and 2. Small red arrow in panel D2 point to transversal mCherry-positive polyclones (see high magnification in E). White arrowheads in panels 3 point to the PML, containing mCherry-positive cells (red arrowhead in D3) (in average, 15% ±4% cells per PML, n=2 fish and 6 sections analysed). E, F. mCherry-positive polyclones induced by a mosaic recombination in her5^actswitch fish at 5dpf and analysed at adult stage. Confocal views of triple-immunostained horizontal sections (areas boxed in scheme), merged panel (E1) includes DAPI counterstaining, single channel panels (E2-4) are color-coded. E. Compared adult expression of mCherry with the RG marker GS (green) and the neuronal marker HuC/D (blue) in her5^actswitch fish. The mCherry polyclones include ventricular RG (small green arrows point to RG cell bodies) and neurons. F. Compared expression of mCherry with PCNA-positive proliferating progenitors, showing that mCherry polyclones contribute to the TPZ (yellow arrows to the TPZ, white arrowheads to the PML) with high magnifications of the boxed area in panel F1. Scale bars: A2-D2 100 µm, A3-D3 50 µm, E,F 20 µm. Abbreviations: Cb: cerebellum, TeO: tectum opticum, TPZ: tectal proliferation zone, TsC: torus semicircularis.