Fig. 1. Expression patterns of ephrinB1, EphB2 and N-cadherin. Changes in Eph/ephrin and N-cadherin expression correlate in space and time with neural crest cell segregation from inter-ganglionic regions and sorting into sympathetic ganglia. Immunohistochemistry performed on HH St. 17 and HH St. 20 sagittal cryostat sections, 15 µm. (A-C) HH St. 17 sections. hnk-1-labeled (green) neural crest cells dispersed adjacent to the dorsal aorta. (D-F) HH St. 20 sections. hnk-1-labeled (green) neural crest cells formed sympathetic ganglia adjacent to the rostral somite. (A) ephrinB1 (red) expressed in caudal somite. Expression ends at ventral edge of caudal somite, arrowheads. (D) ephrinB1 (red) expressed in inter-ganglionic regions between sympathetic ganglia anlagen, arrowheads. (B) EphB2 (red) coexpressed on hnk-1-labeled neural crest cells in the rostral somite and dispersed adjacent to the dorsal aorta. Inset shows separate green channel (hnk-1) and red channel (EphB2). (E) EphB2 (red) coexpressed on neural crest cells that formed sympathetic ganglia. (C) NCD2 (red) expressed on neural crest cells dispersed adjacent to dorsal aorta. (F) NCD2 (red) expressed in sympathetic ganglia. Arrowheads indicate inter-ganglionic region, dashed circles indicate sympathetic ganglia. Scale bars: in C, 20 µm for A-C,F; in E, 20 µm for D,E. c, caudal somite; r, rostral somite; SG, sympathetic ganglia.