(A–P) Lateral views of eyes showing atoh7 fluorescent in situ hybridisation in typical wildtype (A–E, M, O), Ztcf7l1a-/- (F–J), wildtype left-side optic vesicle-ablated (K, L); from n = 5 embryos) and Tg(HS:dkk1)w32 (N, P) embryos at stages indicated. (M–P) Wildtype (M, O) and heterozygous sibling Tg(HS:dkk1)w32 embryos (N, P) heat-shocked at 6hpf (M, N); from n = 7/9 embryos) or 24hpf (O, P); from n = 10/10 embryos) for 45’ at 37°C and grown to 28hpf. Anterior is to the left except in (K) in which anterior is to the right. Arrows indicate ventro-nasal retina; arrowheads indicate dorso-temporal retina; dashed line approximate the nasal-temporal division; dashed circle marks lens position. Abbreviations: n, nasal, t, temporal. Scale bar = 100 µm. (Q) Histogram showing the spatial distribution of atoh7 expression in sibling and Ztcf7l1a-/- retinas at the indicated hours post-fertilisation (data in Supplementary file 1F). VN, ventro nasal expression; VN+, ventro-nasal expression plus a few scattered cells; N+, nasal expression plus scattered cells covering the whole retina; NR, nasal retina expression; WR, whole retina expression; PR, expression localised to the peripheral retina. Numbers in bars represent the number of embryos scored for the particular category of atoh7 expression. (R) Plot showing the growth kinetics of the eye in wildtype (blue line) and Tg(HS:dkk1)w32 (red line) embryos at times indicated (data in Supplementary file 1K).
