Fig. 4. Proximal elements constitute Esr1 and Esr10 proneural enhancers. Sequences driving neural GFP expression of Esr1 and Esr10 constructs are shown schematically in F. (A-E) Xngnr1 mRNA (ngn) with a lacZ tracer mRNA was injected into embryos made transgenic with sequences flanking Esr1, Esr10 and Hairy2. Embryos were stained for GFP by in situ hybridization. GFP expression driven by Esr1/RV (A) and Esr10/Dra (C) is induced by Xngnr1. Esr1/Hin3 (B), Esr10/Pst (D) and the 500 bp H2 flanking sequence (E) are not, indicating that they lack elements responsive to proneural input.