Fig. 4. The mao mutation diminishes the normal loss of Rohon-Beard cell bodies. (A) Dorsal views of two segments from 36 (top) and 72 (bottom) hpf mao mutant and sibling embryos that had been processed for HuA immunocytochemistry (see Materials and Methods). At 36 hpf, mutant and sibling embryos have similar numbers of RB somata. However, at 72 hpf, RB somata have been eliminated in the sibling but retained in the mutant embryo. (B) RB cell counts for mao mutant and sibling embryos at 36 (left) and 72 (right) hpf. Each column represents the mean±s.e.m. for data collected from eight to ten embryos. At 72 hpf, there are significantly more RB somata in mutants versus siblings (P<0.0001). (C) In lateral views of 72 hpf sibling and mutant embryos (top and bottom, respectively), dorsal root ganglia (asterisks) and any remaining RB cells (arrows) can be seen. In siblings, only the dorsal root ganglia are present. By contrast, mutants possess both dorsal root ganglia and RB cells. Scale bars: 20 µm in A; 40 µm in C.