Fig. 8. Repression of projection neuron identity upon constitutive activation of Notch. (A,B) Confocal projections of a control (A) and a Tg(hs:Gal4); Tg(UAS-Nintra) double transgenic (B) embryo 48 hours after a heat shock performed at 9 hours (B). Cells are labeled with HuC/D and with FRet43. (C-E) Average numbers of Islet1+ cells (C), Tg(HuC:GFP)+ (D) and Tg(AANAT2:GFP)+ cells (E) at 48 hours in control and Tg(hs:Gal4); Tg(UAS-Nintra) double transgenic embryos heat shocked at 9 or 24 hours. As the constitutive expression of Notch intra impairs the formation (or the migration) of the parapineal organ, which originates from the epiphysis (Concha et al., 2003), we counted the total numbers of Islet1+ in epiphysis and parapineal in the control embryos. Scale bar: 16 µm. Error bars represent s.d. ^*P<0.05; ^***P<0.0005 using a t-test.