Figure 1

Transverse sections through a stage 21 (E3.5) chick embryo at the level of the developing adrenal gland. (A,B) Steroidogenic factor-1 (SF-1) mRNA (A), a marker for adrenal cortical tissue, is expressed at a location corresponding to the site of bone morphogenetic protein-4 (BMP-4) mRNA expression (B). (C-F) A cluster of cells that express the autonomic markers chick achaete-scute homologue (CASH-1, C) and Phox2B (D), but lack tyrosine hydroxylase (TH) (E) and neurofilament (NF) (F), are located in close proximity to the adrenal cortical anlage. Note that cells at a dorsolateral position of the dorsal aorta, corresponding to developing secondary sympathetic ganglia, express TH and NF. ac, adrenal cortical anlagen; da, dorsal aorta; sg, sympathetic ganglion. Bar: 100 μm.