Fig. 5

Fig. 5 deltaC is Positively Regulated by ascl1a and Receives Negative Feedback by notch. (A) Misexpression of VP16:ascl1a mRNA was sufficient to generate ectopic deltaC expression outside the epidermal ionocyte domain. foxi3a expression, on the contrary, was not affected by VP16:ascl1a mRNA misexpression. (B–F) Evaluation of deltaC expression by genetic mutants or mRNA-injected embryos with enhanced or reduced Notch activity. Compared to the wild-type (B), deltaC expression in the epidermal ionocyte domain was more homogeneous in mib^ta52b (C), bea^tit446 (D), and X-Su(H)^DBM mRNA-injected embryos (E). On the contrary, deltaC expression in the epidermal ionocyte domain was completely abolished in X-Su(H)/Ank mRNA-injected embryos (F). Embryos in the upper panel of all photos are oriented in ventral view, with the anterior to the top, while in the lower panel, all are oriented in lateral view, with the anterior to the left. Epidermal ionocyte domains are highlighted by dotted lines. hpf, hour post-fertilization; tb, tail bud.