Role of ezh2 in oligodendrocyte development: (A) whole-mount RNA in situ hybridization of the brain region of ezh2^+/+ and ezh2^−/− siblings at 2, 3 or 5 dpf, as indicated, to detect olig2 expression as a marker of the oligodendrocyte lineage; (B) whole-mount RNA in situ hybridization of the brain region of ezh2^+/+ and ezh2^−/− siblings at 5 dpf to detect mag or mpz expression, as markers of mature oligodendrocytes. Scale bar is 200 µm; and (C) schematic representation of zebrafish brain organization at 5 dpf. Olfactory bulbs are shown in green, the midline in red, and the cerebellum in blue.

Role of ezh2 in cerebellar progenitor proliferation: (A) whole-mount RNA in situ hybridization of the brain region of ezh2^+/+ and ezh2^−/− siblings at 2, 3 or 5 dpf, as indicated, to detect the expression of the proliferation markers pcna and ccna2. The yellow arrows emphasize expression profile differences in the cerebellum between ezh2^+/+ and ezh2^−/− larvae. Scale bar is 200 µm; and (B) schematic representation of zebrafish brain organization at 5 dpf. The retina is shown in green, the tectal proliferation region in red, and the cerebellum in blue with a black arrow.

Role of ezh2 in cerebellar progenitors: (A) whole-mount RNA in situ hybridization of the brain region of ezh2^+/+ and ezh2^−/− siblings at 2 and 5 dpf, as indicated, to detect the expression of atoh1a, atoh1c and ptf1a. The yellow arrows emphasize atoc1c expression profile differences between ezh2^+/+ and ezh2^−/− larvae. Scale bar is 200 µm; and (B) schematic representation of zebrafish hindbrain organization at 5 dpf. The corpus cerebelli (Cce) is shown in light blue, the lobus caudalis (LCa) cerebelli in dark blue, the valvula cerebelli (Va) in purple, and the eminentia granularis (EG) in yellow.

Role of ezh2 in the differentiation of cerebellar granule and Purkinje cells: (A) whole-mount RNA in situ hybridization of the brain region of ezh2^+/+ and ezh2^−/− siblings at 3 and 5 dpf, as indicated, to detect the expression of neurod1, a marker expressed in immature granule cells, slc17a7a, a marker of differentiated granule cells, and pvalb7, a marker of differentiated Purkinje cells. The yellow arrows emphasize expression profile differences between ezh2^+/+ and ezh2^−/− larvae. Scale bar is 200 µm; and (B) schematic representation of some zebrafish brain structures at 5 dpf. The retina is shown in green, the habenula in black, the torus longitudinalis in brown, the corpus cerebelli (Cce) in light blue, the lobus caudalis (LCa) cerebelli in dark blue, the valvula cerebelli (Va) in purple, and the eminentia granularis (EG) in yellow.

Role of ezh2 in the development of neurotransmitter-specific neuronal populations: whole-mount RNA in situ hybridization of the brain region of ezh2^+/+ and ezh2^−/− siblings at 5 dpf to detect the expression of gad1b, labeling GABAergic neurons, slc18a2, labeling catecholaminergic neurons, tph2, labeling serotonergic neurons, and th, labeling dopaminergic neurons. Scale bar is 200 µm.

Comparison of the locomotor activities between wild-type and ezh2^−/− mutants at 5 dpf: (A) distance traveled throughout a 70 min session for wild-type (yellow, n = 11) and ezh2^−/− mutant (blue, n = 16). Data are presented as mean ± SD of the distance moved (in mm) in 2 min intervals. Black and white bars at the bottom indicate dark and light conditions, respectively; and (B) cumulative distance travelled for each wild-type (yellow) and mutant (blue) larvae during the light (left) and dark (right) periods. Statistical analysis was performed using a Kruskal–Wallis test followed by Dunn’s post hoc test. **, p <0.05.