Igf1r Signaling Is Indispensable for Preimplantation Development and Is Activated via a Novel Function of E-cadherin
Figure 3
Markers for lineage specification, cell polarity, and vectorial fluid flow are correctly expressed and localized in NcEc homozygous mutants.
(A) Proper segregation of outer TE cells is shown by anti-Cdx2 labeling in wt, EcNc and NcEc homozygous mutants at E3.5. (B) Wildtype, EcNc and NcEc homozygous mutant embryos labeled for the ICM cell marker Sox2 in inner cells, showing ICM cell specification and its localization inside NcEc homozygous embryos. (C) Ezrin and Na+/K+-ATPase staining to verify apical-basal polarity with same distribution in wt, EcNc and NcEc homozygous mutants at the apical and basolateral membrane. Correct sealing of the TE layer is indicated by the presence and proper localization of the tight junctional component ZO-1 at apical sites of lateral TE membranes in wt, EcNc and NcEc homozygous embryos. Key components required for vectorial fluid transport are shown by the presence of Na+/K+-ATPase and Aqp3. In embryos of all genotypes, this expression is detected in the outer cells, without any obvious differences in expression between the embryos. Hence, the first lineage segregation is specified correctly, and proteins that are essential for the TE formation process and its function are present and properly localized in NcEc homozygous mutants. Nuclei were labeled with DAPI (blue). Scale bar, 25 µm.