Fig. 1. Slug overexpression increases neural crest production in the chick hindbrain. (A) Stage 13 control embryo showing the normal Slug expression in the premigratory and migratory neural crest. (B-D) Embryos electroporated with plasmids containing chick Slug and GFP cDNAs, injected with DiI at stage 9 and analysed 15 hours later (stage 13-14). GFP expression is observed in the right hand side of the neural tube and in cells migrating from this side (B). DiI labelling is observed within the neural tube and in all crest cells that have emigrated from the neural tube after electroporation (C). (D) HNK-1 staining in the same embryo. Both DiI labelling and HNK-1 immunohistochemistry confirm the increase in neural crest production in the electroporated side. White arrows in C indicate the r4 and r6 crest streams where an increase in the migratory cell population can be observed when compared to the control side. Black arrowhead shows DiI-labelled cells adjacent to rhombomere 5 (see also Fig. 2H). A representative section taken at the level of r4 is shown in E to better assess the relative increase in crest production. (F-H) A section taken from a different embryo at the level of r6 showing (F) exogenous GFP-Slug expression, (G) DiI labelling and (H) the merged image. ov, otic vesicle; r, rhombomere. In all experiments, the control side is to the left.
