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Fig. 8. N- and E-cadherin cannot replace each other in the neural and non-neural ectoderm. (A,B) The same field of view in brightfield and fluorescence. Injection of N-cadherin MO + RLDX into both dorsal animal cells at the 8-cell stage, thus depleting N-cadherin in most or all of the neural plate, blocks neural fold closure (compare upper row of untreated embryos with middle row of MO-injected embryos). This is rescued by subsequent injection of X. tropicalis (MO-resistant) N-cadherin mRNA into the same cells (lower row of embryos). (C,D) Equivalent pictures to show that injection of E-cadherin mRNA does not rescue neural fold closure. The lower row of embryos has received MO + E-cadherin mRNA. (E) A higher magnification field of view to show that F-actin is not rescued by E-cadherin mRNA (compare control to N-cad MO + E-cad mRNA panels), although the E-cadherin protein is expressed (stained red in the cross-section view with anti-E-cadherin antibody). (F) Four images of the same en face field of view of a clone of cells (asterisk, blue in right-hand panels) depleted of E-cadherin, and subsequently injected with Myc-tagged N-cadherin mRNA. The N-cadherin protein is expressed (stained red with anti-Myc antibody), but does not rescue the loss of F-actin (green) caused by E-cadherin depletion. The cells along the border between untreated cells (#; which express E-cadherin) and cells in which E-cadherin has been replaced by N-cadherin (arrows), do not express N-cadherin on the cell surface adjacent to E-cadherin-expressing cells. Scale bars: 100 μm. |
