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Fig. 6. Depletion of E-cadherin in the ventral (non-neural) ectoderm causes reduction of F-actin. (A,B) Injection of E-cadherin MO into single ventral animal cells (arrow in A) gives rise to large clones of cells depleted of E-cadherin protein (lower panel in A, B). Arrows in B indicate boundaries between injected cells (*) and uninjected cells (#), which express E-cadherin. (C) Reduction of F-actin in E-cadherin-depleted cells (*) as compared with uninjected cells (#). (D,E) Reduction, but not absence, of F-actin in E-cadherin-depleted cells (D, lower panel), probably because of continued expression of C-cadherin, as shown en face and in cross-section in E. (F) Most of the non-neural ectoderm is labeled by injection of both ventral animal cells at the 8-cell stage. The same embryo is shown in the center and lower panels during neural fold closure, which is delayed compared with untreated embryo (left) owing to reduced pushing movements of the non-neural ectoderm (NE). (G) Rescue of the cortical actin skeleton by injection of an MO-resistant form of E-cadherin mRNA into the cell injected with E-cadherin MO. The asterisk marks the treated cells; #, adjacent untreated cells. Four images are shown of the same field of view. The RLDX (blue) and anti-HA (red) staining show the expression of the HA-tagged mRNA in the same cells as those injected with the MO (co-injected with RLDX), whereas the Phalloidin staining (green) shows increased assembly of F-actin in the injected cells (compare with C, where actin staining is reduced in the MO-injected cells). Scale bars: 100 μm in B,C,G; 20 μm in D,E. |
