Fig. 1. Neural crest cells avoid substrate-bound ephrin stripes. Neural crest cells avoid stripes of substrate-bound ephrin-B2-Fc, undergoing repeated cycles of lamellipodial protrusion and collapse at sites of contact with ephrin-B2-Fc. (A) Cells distal to the neural tube explant avoided the ephrin-B2-Fc stripes and exhibited a striped pattern on the coverslip. (B) Neural crest cells on negative control stripes failed to discriminate between the sets of stripes. (C) Neural crest cells that contact substrate-bound ephrin-B2-Fc (lighter broader stripe) undergo a dramatic loss of lamellipodia (black arrow). (D) Neural crest cells undergo cycles of protrusion (red arrows) and retraction (black arrows) along the edges of substrate-bound ephrin-B2-Fc stripes. (E) Retraction from ephrin-B2-Fc (pink overlay) is associated with membrane ruffling (black arrows) and the internalisation of phase bright vesicles (red arrows). A red asterisk denotes the cell to which timepoints refer. Bars, 130 µm; ephrin stripes are 40 µm wide.