Investigation into the mechanisms mediating the dorsal migration of sympathetic ganglia

The neural crest is a migratory population of cells that produces many diverse structures within the body. Trunk neural crest cells give rise to such structures as the dorsal root ganglia (DRG) and sympathetic ganglia (SG), which form in a metameric pattern along the anterior‐posterior axis of the embryo. Sympathetic ganglia precursors migrate through the rostral portion of each somite, disperse in the anterior‐posterior direction along the dorsal aorta and re‐segregate to produce discrete ganglia. SG precursors then respond to BMPs at the dorsal aorta to begin their neural differentiation. Strikingly, this chain of primary sympathetic ganglia are transient structures. Within hours of their formation, sympathetic precursors within the primary chain migrate dorsally towards the ventral surface of the DRG and form the permanent, secondary chain of sympathetic ganglia. As this migration ensues, the original primary chain disappears. The molecular and cellular mechanism driving this secondary migration are not at all understood. Here, we use time‐lapse confocal microscopy to image in real‐time the migration of sympathetic precursors as they move from primary chain to form the secondary chain and reveal extensive cell‐cell and cell‐environmental interactions are important for proper SG development.