Fig. 4

Lmo4 expression in spg/pou2 and ace/fgf8 mutant embryos and in response to soluble Fgf. Embryos of various genotypes (as shown in the top right corner of each panel) were analyzed with various probes (as indicated in the lower right corner of each panel). In situ hybridization and immunostaining were done as reported (Sagerström et al., 2001 and Schulte-Merker et al., 1992). (A, C, E, G, I, K) Wild type embryos; (B, D) spg mutant embryos; (F, H, J) ace mutant embryos. (K, L) Wild type embryos into which an Affi-Gel bead soaked in MBS (K) or 0.5 mg/ml Fgf (L) was implanted at shield stage (6 hpf). (A–D) were hybridized to noi/pax2.1 (indicated by asterisks) and lmo4 probes (brackets in A, B). (C, D) are focused in the plane of the ectoderm. (E–H) and (K, L) were hybridized to a lmo4 probe and (I, J) were stained with the dP-ERK antibody (Sigma Cat. # M8159) at a dilution of 1:1000. All whole-mount embryos are dorsal views with anterior to the top. Transverse 10 μm sections in (G, H) are cut through the presumptive rostral hindbrain area that shows maximal lmo4 expression in wild type bud stage embryos. Dorsal is at the top. All embryos are at bud stage (10 hpf) except (C, D), which are at the two-somite stage.