Fig. 7

RA pathway activation accelerates retinal neurogenesis. (A-F) Lateral views of eyes of wild-type (A,B) or Tg[atoh7:GFP] (C-F) embryos treated with AM580 (B,D,F) or vehicle control (DMSO; A,C,E) fixed at the times indicated to the left of the rows, and showing expression of either atoh7 (purple; A,B) or immunostained for GFP (green; C-F). (G-J) Lateral views of eyes of gdf6a^u768 mutants expressing the atoh7:GFP transgene treated with BMS614 (H,J) or vehicle control (DMSO; G,I), fixed at the times indicated to the left of the rows, and immunostained for GFP (green). Note that GFP expression does not extend beyond its ventronasal initiation site in the BMS614-treated eye at 28hpf. (K,L) Graphs showing average proportional volume of retina containing atoh7:GFP-positive cells at 28 and 40hpf in the conditions indicated along the x-axes for activation (K) and suppression (L) of RA pathway, plotted with standard error bars (95% confidence limits; n=5 embryos for each condition). (M,N) Transverse cryosections of wild-type sibling (M) and gdf6a^u900 (N) eyes at 80hpf showing expression of the atoh7:GFP transgene (green) and counterstained nuclei with DAPI (red). White arrows show ectopic GFP-positive cells in the inner nuclear layer. (O) Graph of the average number of atoh7:GFP-positive cells per area of retina in wild-type and gdf6a^u900 mutant eyes (n=6; standard error bars, 95% confidence limits; Student′s t-test **P=0.0014).