Fig. 1. Control of Notch-dependent endoderm expression. (A) Diagram of the two Notch interactions in the endoderm. Cells in the endoderm primordium that are activated by Notch signaling are shown in green. (B-G) The top and bottom panels show embryos at the E8 and E16 stages, respectively, with anterior at top. Images were taken through the plane of the intestinal primordium (outlined in black); the E16 primordium appears smaller than the E8 because the posterior end curves downward, out of the focal plane. (B) Differential interference contrast (DIC) micrographs. (C-F) Fluorescence micrographs of embryos with wild-type or mutant enh^A::GFP transgenes; mutations were introduced into either pAN20 or pKG55 (Fig. 2A). (C) Wild-type enh^A::GFP (pAN20); the onset and pattern of GFP expression in the endoderm is identical to ref-1::REF-1::GFP expression described previously (Neves and Priess, 2005). (D) CSL sites mutated to RAGGCAA (pAN20). (E) WGATAR sequences mutated to WCATAR (pKG55). (F) Candidate NK site mutated to CTCAAGTT (pAN20). (G) Wild-type embryos depleted for ELT-2/GATA by RNAi (GFP reporter is ANPCR in Fig. 2A).