Fig. 7.
Dysmorphogenesis of the labyrinth layer in Del7AI/+ placentae. ISH for (A) Prl3b1 and (B) Gcm1 on frozen sections of wild type and mutant placentae at E15.5. Multiple sections from two placentae of each genotype were assessed and representative sections are shown. Sense probes are not shown. The blue stain shows gene expression. Prl3b1 is expressed in parietal trophoblast giant cells, spongiotrophoblast and mononucleated sinusoidal trophoblast giant cells of the labyrinth. In the mutants, the spongiotrophoblast staining is replaced by a thicker giant cell layer, and the labyrinth signal is denser. Gcm1 is a marker of the syncytiotrophoblast II of the labyrinth. As seen for Phlda2 (expressed in syncytiotrophoblast I) and Prl3b1, we observed a denser network of Gcm1-expressing cells in the mutant placenta. (C) IHC for laminin marks the basement membrane of the fetal blood vessels and revealed a denser network of capillaries in the mutant labyrinth. The brown stain shows protein expression. (D–E) Feto-placental vasculature of the maternal Del7AI heterozygotes. Representative scanning electron micrographs of E14.5 fetal vascular corrosion casts. (D) Lateral view; (E) top view from maternal side. Four fetal vasculature casts were assessed per genotype. Scale bar: 1 mm.