Fig. 7. fezl overexpression is sufficient to repress wnt1 and to restore anterior forebrain gene expression in Headless and/or Tcf3-deficient embryos. (A-L) Analysis of gene expression. The hdl/tcf3 morpholino was injected into one- to eightcell-stage embryos derived from the hsp-gal4/+xuas-fezl cross. These hdl/tcf3 morphants were subjected to heat shock at 75% epiboly, analyzed for forebrain gene expression at 28 hpf with various markers (as specified in each panel) and subsequently genotyped for the presence or absence of the transgenes. In general, three classes of phenotypes were observed for each marker, and their percentage distributions in the non-transgenic heat-shocked hdl/tcf3 morphants versus in the double transgenic heat-shocked hdl/tcf3 morphants are indicated above each panel. A-C,G-I are dorsal views and D-F,J-L are lateral views. Insets in G-I show lateral views of the same embryos. Arrow in C represents residual wnt1-expressing cells. tel, telencephalon; ba, branchial arches.