Fig. 1. Adrenal cortical cells are labelled by Sf1 in-situ hybridization on a transverse section (dorsal, top) of an E13.5 wild-type embryo (A). Sf1 expression is completely lacking in Sf1^–/– littermates (B). In-situ hybridization for NF mRNA (blue) and TH immunofluorescence staining (red overlay) have been performed on a consecutive section of the wild-type (C; E, higher magnification) and the Sf1^–/– embryo (D; F, higher magnification). Note that in Sf1^–/– embryos TH⁺/NF^– `adrenal' chromaffin cells accumulate at a location where the adrenal gland develops in wild-type mice. Scale bars: 100 µm. a, dorsal aorta; gn, gonadal anlage; sg, sympathetic chain ganglion; srg, suprarenal ganglion.