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Fig. 9
otx2:venus expression in the adult zebrafish midbrain. (A) Schematic representation of the adult zebrafish brain. The position of the cross section of the midbrain with optic tectum, hypothalamus, and pituitary shown in panel (B) is indicated (orientation indicators A->P: anterior to posterior; D->V: dorsal to ventral). (B) Cross section of the midbrain labeled with otx2:venus (green), the pan neuronal marker HuC/D (red) and the nuclear counterstain DAPI (blue). (C) Higher magnification image of the region indicated by white box in panel (B) showing that numerous neurons express otx2:venus. (D–F) Higher magnification images of the regions indicated by white boxes in (C). otx2:venus is co-expressed in HuC/D expressing neurons (yellow arrowheads) in the various tectal sub layers that is characteristic of a teleost midbrain. However, a sub-population of HuC/D positive neurons was negative for otx2:venus (white arrowheads). (D) Type III horizontal neurons that belong to the stratum opticum. (E) Projection neurons that mostly belong to the stratum griseum et album superficiale and centrale regions. (F) Prominent unipolar type XIV interneurons located in the periventricular gray zone of optic tectum. Anatomical descriptions are based on the zebrafish brain atlas (Wullimann et al., 1996), tectal sub layers and neuronal types were interpreted based on Meek (1981) and Meek and Schellart (1978). Scale bars (B): 100 μm; (C): 20 μm; (D–F): 5 μm. (B,C: maximum intensity projection; D–F: single Z-Plane).