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Fig. 9 Notch signaling inhibits both cell-cycle exit and neurogenesis in the retina. (A-D) BrdU labeling in wild-type (A), add (B), mib (C) and add; mib mutant retinas. BrdU incorporation is suppressed in the central region of the add; mib double mutant retina (D, asterisk). (E-H) ath5 expression in wild-type (E), add (F), mib (G) and add; mib (H) mutant retinas. ath5 expression is severely inhibited in add mutant retinas, is enhanced in mib mutant retinas and is partially restored in the add; mib double mutant retinas (H, asterisk). (I,J) BrdU labeling of mib mutant injected with the DNA construct pCS2[hsp:EGFP] (I) and with pCS2[hsp:Δ47-ß-catenin-GFP] (J). Cells expressing Δ47-ß-catenin (green, inset in J) are BrdU-positive (red), even in the central region of mib mutant retinas (J), while cells expressing EGFP are BrdU negative in the central region of mib mutant retinas (I). (K,L) BrdU labeling of wild-type retina treated with TSA (K) and mib mutant retina treated with TSA (L). Treatment with 400 nM TSA from 10 hpf induces more severe phenotypes than that from 14 hpf shown in Fig. 5F. (M,N) Plastic sections of retinas of wild-type retina (M) and wild-type retina expressing NICD (N). Wild-type retina expressing NICD is folded in the same way as the add mutant retina (arrowheads). (O,P) Labeling of wild-type (O) and NICD-expressing (P) retinas with zn5 antibody, which labels retinal ganglion cells (red). Nuclei were counterlabeled with Sytox Green (green). (Q,R) BrdU labeling of wild-type (Q) and NICD-expressing retinas (R). In both cases, BrdU incorporation is not observed in the central retina. Broken white lines show the interface between the brain and retina. (S,T) Labeling of wild-type (S) and NICD-expressing retinas (T) with anti-glutamine synthetase antibody, which labels Müller glia (red). Glial cells differentiate precociously in the NICD-expressing retina (arrowhead)