Fig. 5. The normal downregulation of N-cadherin protein along the axis is regulated by BMP4. (A-D) Treatment with BMP4-coated beads (^* in B,C; n=7) or electroporation with BMP4-DNA/GFP (arrowhead in D; insert depicts localization of transfected BMP/GFP; n=8) for 8 hours downregulates N-cadherin immunoreactivity at levels of rostral and caudal segmental plates. At these levels, N-cadherin is still expressed in the dorsal NT under normal conditions (A) and in matching controls (not shown). (E,F) Sections through a dissociating somite level 15 hours after electroporation of control-GFP (E; n=8) and noggin-GFP (F; n=9). (E) Note the absence of N-cadherin in the dorsal NT from which N-cadherin-negative NC cells emigrate (arrows depict phase-bright NC in main image and GFP+ NC in insert). (F) By contrast, noggin overexpression (green cells in insert and surrounding area) maintains N-cadherin and no NC emigration is apparent. Similar results were obtained by staining with anti-N-cadherin antibodies directed to either the extracellular or intracellular domains of the protein; the data presented stem from the latter. Abbreviations: CSP, caudal segmental plate; RSP, rostral segmental plate; scl, sclerotome. Scale bar: 25 µm.