shh and foxa2 expression is disrupted in the anterior endoderm of pbx4- and meis-deficient embryos. (A) shh is expressed in the anterior endoderm (ae) and fin buds (fb) of 48 hpf wild type embryos. (B) lzr mutants (as identified by the absence of pectoral fin buds) exhibit reduced shh expression in the anterior endoderm. (C–E) shh expression is reduced in the anterior endoderm and fin buds of embryos injected with the dominant negative Meis construct (ΔCPbx4). Variations in the severity of the ΔCPbx4-mediated phenotype are likely due variable distribution of the injected mRNA, as routinely seen with this type of injections. (F–H) Prominent sites of neurectodermal shh expression (black arrows) are unaltered in lzr mutant and meis-deficient embryos. (I) foxa2 is expressed in the anterior endoderm of 48 hpf embryos. (J, K) Disruption of foxa2 expression in lzr mutant and meis-deficient embryos is similar to that seen for shh. Dashed black lines outline the normal expression domains of shh (A-E) and foxa2 (I-K) in the endoderm. Dorsal views in panels A-E, I-K; lateral views in panels F-H. Anterior is to the left in all panels.
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