Fig. 3
The last S-phase of early-born olfactory neurons is delayed in the neurog1 mutant zebrafish. (A-F) Confocal sections of olfactory placodes immunolabelled for BrdU (red) and GFP (green) from the Tg(8.4neurog1:GFP) transgene in wild-type (A-C) or neurog1 mutant (D-F) embryos at 24 hpf (A,B,D,E) or 28 hpf (C,F). The stages at which BrdU incubation were started is indicated. Scale bars: 10 μM. (G) The proportion BrdU+;GFP+ cells over total number of GFP+ cells in the olfactory placode after BrdU treatment in wild-type (green line) or neurog1 mutant (red line) embryos. Although early-born olfactory neurons generally leave the cell cycle later in mutant than in wild-type embryos, at 24 hpf few, if any, early-born olfactory neurons are still cycling in either genetic context. Error bars represent s.d.