Fig. 4

Fig. 4 Global overexpression of ascl1a induces supernumerary and ectopic th+ neurons. (A) Experimental timeline of heatshock overexpression experiments. Embryos from a Tg(hsp70:ascl1a) outcross were heat shocked at 12 hpf and fixed at 30 or 72 hpf for analysis (A, B-E″). (B–E) Whole-mount in situ hybridization for th (B-E″) and ascl1a (G), stages as indicated. Dorsal views (D″,E″) and lateral views (B,B′,C,C′,D,D′,E,E′), genotypes as indicated. (G) Heat shock leads to a global overexpression of ascl1a in Tg(hsp70:ascl1a) outcrosses. (B–C′) Tg(hsp70:ascl1a)+ embryos have ectopic th+ neurons in the peripheral nervous system (arrowheads) when compared to wildtype siblings at 30 hpf. (D-E″) At 72 hpf Tg(hsp70:ascl1a)+ embryos have ectopic th+ neurons in the peripheral nervous system (arrowhead) and additional neurons of the LC. Box with dashed lines in D and E mark magnified part in D′ and E’ (D″ and E’‘: dorsal views of regions corresponding to lateral views in D′ and E′). (F) Summary of the observed phenotypes. For numbers of analyzed embryos see Supplemental Table S2. Abbreviations: hs, heat shock; LC, locus coeruleus; PNS, peripheral nervous system; WISH, whole mount in situ hybridization. Anterior is to the left. Scale bars: 100 μm.