Cell fate restriction of late-born trigeminal sensory neurons is independent of early-born neurons. Subpopulation markers were analyzed in embryos lacking early-born trigeminal sensory neurons. (A-D) Embryos carrying the p2x3b:egfp (A,B) or trpa1b:egfp (C,D) transgene were injected with 6 ng of neurogenin1 morpholino (B,D) and imaged at 72 hpf. Although both p2x3b-expressing and trpa1b-expressing neurons are visible in uninjected larvae (A,C), only p2x3b-expressing are detectable in neurogenin1 morphant larvae (B). No trpa1b-expressing neurons were detected in these larvae (D). (E-H) Wild-type (E,G) and neurogenin1 morphant (F,H) larvae were stained by in situ hybridization at 96 hpf for p2x3b (E,F) or trpa1b (G,H). No trpa1b-expressing neurons were detected in neurogenin1 morphant larvae (H). Side view, anterior towards the left. Scale bars: 10 μm.
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