Figure 11

Outgrowth of cranial neural crest cells from stage 10–12 chicken neural tube explants onto ephrin-B1 or EphB2 stripe assay substrates in the presence of soluble competitors. Representative results from the four experimental conditions. The position of the first set of lanes is revealed by an FITC marker (faint green stripes). Cells have been double labeled with HNK-1 antibody (red) and DAPI nuclear stain (blue). All experiments were done with a stripe protein concentration of 64 μg/ml. (a). Clustered ephrin-B1/Fc + FN vs. FN with soluble Fc. Cell outgrowth from the neural tube is strongly localized to the lanes between stripes of FITC-marked ephrin-B1/Fc. (b) Clustered ephrin-B1/Fc + FN vs. FN with soluble ephrin-B1/Fc. Substitution of the soluble Fc with ephrin-B1/Fc results in an increase in the number of cells found on the stripes of immobilized ephrin-B1/Fc. (c) Clustered EphB2/Fc + FN vs. FN with soluble Fc and (d) clustered EphB2/Fc + FN vs. FN with soluble EphB2/Fc. As with the ephrin-B1/Fc experiments, there is a significant increase in the number of cells on lanes of substrate-bound EphB2/Fc in going from adding soluble Fc to soluble EphB2/Fc to the culture medium.