Fig. 3. Expression of N-cadherin during the second wave of myotome development. (A,H,K) Desmin (green); (B,E,F,I,L) N-cadherin (red); (C,J,M) overlay of desmin and N-cadherin, nuclear Hoechst is blue. (D-G) Electroporation of GFP/DNA into a rostral DM lip (green in D and G) co-stained for N-cadherin (E-G). (A-G) Flank somites of E3 embryos. (A-C) The apical surface of the DM and desmin⁺ fibers express N-cadherin (arrowhead). (D-G) Semi-frontal section showing that the GFP⁺ epithelial cells in the rostral lip co-express N-cadherin. Note in F and G that, like in the DM sheet, N-cadherin is restricted to the apical aspect of the cells (arrows). (H-M) Transverse sections through flank somites at E4. (H-J) High magnification of the DML region showing the myotome and DML positive for N-cadherin. The latter displays strong apical N-cadherin staining (arrowhead). Cells within the SLD (delineated between arrows) express N-cadherin but are desmin negative; note that their cell and nuclear shapes are rounder than the elongated epithelial cells of the DML. (K-M) Dermal cells (D) downregulate N-cadherin expression to a basal level. Scale bar: 80 µm in A-C,K-M; 40 µm in D-E; 20 µm in F-I.