Fig. 7

Fig. 7

Loss of retinoic acid suppresses pLLp formation via the activation of Fgf signaling. The duration of the heat shock to activate Fgf signaling and timing for fixation are indicated on the top-left for (A-D), and for (E-H). Condition for heat shock is “39 °C for 20 min ->room temperature for 20 min ->39 °C for 20 min”. After fixation embryos are subjected to in situ hybridization. Numbers of embryos showing this expression pattern are indicated in the top-right corners. The larger number is the number of all embryos, not the number of embryos transgenic for CA-FgfR1. Because the transgenic parental fish were heterozygous, and we crossed them with wild type, we expected a ratio of transgenic embryos of 50%. A, B, E, F are flat-mounted embryos at 12 hpf (A, B) and 14 hpf (E, F) stained with eya1 and hmx3+pax2a, respectively. Anterior to the left. C, D, G, H are the lateral side views of 12 hpf (C, D) and 14 hpf (G, H) embryos stained with pea3. Anterior is to the top in C, D, and to the left in G, H. (I-T) Rescue experiments with the Fgf inhibitor SU5402. Duration of the drug treatment (0.9% DMSO, 10 µM DEAB, 80 µM SU5402) is indicated on the top. I-L are flat-mounted embryos at 14 hpf stained with hmx3+pax2a. M-T are left-side views of 14 hpf embryos stained with pea3 (M, O, Q, S) and hoxb1b (N, P, R, T). White arrowheads indicate the anterior edge of the neural hoxb1b expression, and the black one points at the posterior extension of pea3 in (O). Black arrow in (L) marks rescued hmx3 expression. Colored bars indicate the positions of the aLLp, otic vesicle and pLLp. Abbreviations: aLLp: anterior lateral line placode, ov: otic vesicle, pLLp: posterior lateral line placode. Scale bar: 100 µm.