Fig. 2. Esr1 and Esr10 are expressed in proneural domains. Esr1, Esr10 and Delta are expressed in the neural tube (A,D,G, white arrowhead), cranial ganglia (A,D,G, arrow) and anterior neural tube (B,E, arrowhead). Esr10 is also expressed in the tailbud (D, black asterisk) and somitomeres (D, white asterisk). Delta1 is also seen in somitomeres (G, white asterisk), although the Notch ligand predominantly expressed in the tailbud is Delta2 (Jen et al., 1997). At neurula stages, Hairy2 is barely detectable in the neural tube (J) but expressed in presumptive neural crest (K, arrowhead). Hairy2 expression in the eye (K, arrow) precedes that of Esr1 and Esr10. Misexpression of mRNA encoding Xngnr1 induces Esr1 (C), Esr10 (F) and Delta1 (I); C', F' and I' show uninjected sides. Hairy2 is not upregulated by misexpressed Xngnr1 (L; L', uninjected side). Turquoise stain in C,F,I,L reflects activity of the lacZ tracer gene. (M, left) RNase protection assay showing that expression of Xngnr1 in neuralized animal caps analyzed at stage 12 induces Esr1 and Esr10 that can be inhibited by expression of SuH, and in the case of Esr1, further increased by co-injection of ICD. EF1a expression serves as a loading control; `Embryos' indicates staged-matched controls. Quantification (right) shows fold increases in Esr1 and Esr10 relative to their respective `noggin only' control, which is set arbitrarily to 1.