Disorganized epithelial polarity and excess trophectoderm cell fate in preimplantation embryos lacking E-cadherin

• DOI: 10.1242/dev.050195
• Publication Date: 2010-09-09T00:59:21Z
• Authors: Robert Odell Step...; Yojiro Yamanaka; Janet Rossant
• Keywords: Inner cell mass; CDX2; Cell polarity; Epithelial polarity; Trophoblast

The first two cell lineages in the mouse, surface trophectoderm (TE) and inner mass (ICM), are morphologically distinguishable by E3.5, with outer TE forming a polarized epithelial layer enclosing apolar ICM. We show here that mouse embryos completely lacking both maternal zygotic E-cadherin (cadherin 1), normal morphology of outside cells is disrupted, but individual still initiate TE- ICM-like fates. A larger proportion than showed expression markers such as Cdx2, suggesting formation an organized epithelium not necessary for TE-specific gene expression. Individual generated apical domain correlated elevated Cdx2 also repolarization can occur isolated early ICMs from wild-type mutant embryos, indicating required initiating polarity. results demonstrate integrity mediated expression, essential allocation ICM cells. They strongly linked to membrane polarization.