Fig. 5

Conditional activation of Notch signaling produces excess KA' interneurons at the expense of PMNs. (A-F) Lateral views of the spinal cord of zebrafish embryos at the 6- to 12-somite region, with anterior to the left and dorsal at the top. (A,B) Control Tg(UAS:Notch1a^ac-myc);Tg(olig2:egfp), (C,D) Tg(hsp70l:gal4vp16);Tg(UAS:Notch1a^ac-myc);Tg(olig2:egfp) and (E,F) Tg(hsp70l:XdnSu(H)myc);Tg(olig2:egfp) embryos were heat shocked at 11 hpf. (A,B) Control embryos showed normal numbers of isl2⁺ PMNs (black bracket), dorsal Rohon-Beard sensory neurons (white bracket) and GABAergic KA' cells (arrowheads). (C) isl2⁺ PMNs (black bracket) and Rohon-Beard neurons (white bracket) were almost absent from heat-shocked triple-transgenic embryos. (D) Heat-shocked triple-transgenic embryos had excess KA' interneurons (arrowheads). (E,F) Heat-shocked Tg(hsp70l:XdnSu(H)myc);Tg(olig2:egfp) embryos had excess PMNs (black bracket), excess Rohon-Beard neurons (white bracket) and a deficit of KA' interneurons (arrowheads). (G) Mean of the number of PMNs (gray bar) and KA' interneurons (black bar) per hemisegment (n=7) in A-F. Error bars represent s.e.m. Scale bar: 50 µm.