Fig. 4

Loss of miR-107 Function Promotes Embryonic Hindbrain Neurogenesis

(A and B) Schematic representation of the experiments in (C and D) and (E), respectively.

(C) Hindbrain cross-sections showing brief BrdU pulse labeling of miR-107a^+/+ and miR-107a^-/- mutants at 30, 48, and 60 hpf. (Right) High magnifications of the area boxed in the left. White arrows indicate supernumerary BrdU⁺ cells. Gray dashed line indicates the hindbrain area.

(D) Number of BrdU⁺ cells per section in (C) and in the MO^107a- and MO^ctrl-injected embryos treated in the same conditions. Data are shown as mean ± SEM of two independent experiments for miR-107a mutants and three for the morphants (n = 5 to 10 embryos each). p < 0.05.

(E) (Top) Hindbrain cross-sections of 60 hpf miR-107a^+/+ and miR-107a^-/- mutants stained for BrdU and HU. (Right) High magnifications of the boxed area in the left. Arrows indicate the increase of BrdU-HU double-positive cells migrating in the mantle area (dashed line). (Bottom) The quantification of the number of BrdU-HU double-positive cells in the indicated samples. Data are shown as mean ± SEM of two independent experiments for miR-107a mutants and three for morpholino (n = 5 to 10 embryos each). p < 0.05.

(F) Expression of ngn1 in 107a^+/+ and 107a^-/- mutants at 60 hpf. Dorsal is up, and anterior is to the left. White stars indicate increased ngn1 staining. The graph shows the quantification by qRT-PCR of miR-107 and ngn1 expression levels in 107a mutants and in MO^107a-injected embryos. Levels are relative to the respective controls (107a^-/- and MO^ctrl, respectively). Data are shown as mean ± SEM. p < 0.05. Scale bars represent 50 µm.