Fig. 3. Development of the primary sympathetic ganglion chain. Whole-mount in situ hybridization staining of the sympathetic nervous system using a Phox2a antisense riboprobe on E12.5 embryos. Mid-sagittal views of (A) Erbb2^wt/Erbb2, (B) Erbb2^Erbb2/ko, (C) Erbb2^wt/Y1028F, (D) Erbb2^Y1028F/ko. Black arrowheads point to the superior cervical ganglia; white arrowheads highlight the thoracic sympathetic chain ganglia; green and blue arrowheads indicate the cells that migrate from the caudal portion of the primary sympathetic chain to the mesentery or the anlage of the adrenal gland.