Notch inhibition during larval development leads to an increase in dorsal root ganglia (DRG) neurons. (A-B) Confocal projections of Tg(neurog1:EGFP) DRG neurons labeled with anti-GFP (green) and Elavl (red) from larvae treated with DMSO or DAPT between two and five dpf. At five dpf, DRG neurons are labeled by Elavl (yellow arrowhead) and a subset also express GFP (white arrow) in both DMSO (A) and DAPT (B) treated larvae. (C-D) Confocal images of Tg(hsp70l:XdnSu(H)myc); Tg(neurog1:EGFP) larvae following heat-shock (HS) beginning at two dpf. In control (C) and transgenic (D) larvae at five dpf after HS, DRG neurons were labeled with GFP (green) and Elavl (red). Larvae carrying the Tg(hsp70l:XdnSu(H)myc) transgene were identified by ectopic myc labeling (blue, white asterisk) following HS. (E) Quantification of DRG neurons following Notch inhibition with DAPT or HS in Tg(hsp70 DN (Su(H) myc) embryos from two to five dpf. There is a significant increase in the number of DRG neurons in DAPT-treated and myc-positive larvae as compared to control larvae. (n = 6 for DMSO- or DAPT-treated larvae, n = 10 for myc-negative larvae and n = 13 for myc-positive larvae, five ganglia per larvae, *P <0.03, Student’s t test). (F) Quantification of DRG neurons in TgBAC(neurod:EGFP)-positive DRG following Notch inhibition with DAPT from two to five dpf. There is a significant increase in the number of DAPT-positive DRG neurons as compared to control embryos. (n = 9 for DMSO or n = 8 for DAPT-treated larvae, five ganglia per larvae, *P <0.005, Student’s t test). Scale bars, 20 μm. DAPT, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester; DMSO, dimethyl sulfoxide; dpf, days postfertilization GFP, green fluorescent protein.