mortality/aging
• by E8.5, homozygous mutant embryos are in the process of resorption
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embryo
• at E7.5, homozygous mutant embryos show defects in gastrulation and in the epithelial-mesenchymal transition required for normal formation of the mesoderm cell layer
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• at E7.5, most mutant embryos exhibit cavities or lacunae in the mesoderm layer, and the mesoderm cells lining these lacunae retain the morphology of an ordered columnar epithelium instead of having the typical mesenchymal morphology of wild-type mesoderm cells
• mutant mesoderm displays an apical-basal polarity that is characteristic of an epithelial cell layer
• mutant mesoderm cells contain microvilli at the apical surface facing into the lacunae and display numerous electron-dense adhesive junctions between cells
• at E7.5, E-cadherin expression is abnormally retained in the mesoderm of mutant embryos, although at lower levels than those observed in embryonic ectoderm
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• by E8.5, homozygous mutant embryos appear severely retarded relative to wild-type embryos
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• at E7.5, homozygous mutant embryos are smaller than wild-type embryos
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absent amnion
(
J:72861
)
• although a posterior amniotic fold forms, no amnion is observed at E7.5
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• no chorion is observed at E7.5
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growth/size/body
• by E8.5, homozygous mutant embryos appear severely retarded relative to wild-type embryos
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• at E7.5, homozygous mutant embryos are smaller than wild-type embryos
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