Expression of Calbindin-D9k in the Columnar Epithelial Cells of the IPY
As previous studies have indicated that the expression of calbindin-D9k is the sole specific marker for the IPY in the mouse placental disc, we next examined whether or not ISH using antisense probe for our cloned putative mouse homologue of calbindin-D9k could detect the columnar epithelium of the IPY. The result of the ISH is shown in Figure 1, G and H and Figure 4, В and F. Strong signals were detected in the columnar cells of the sinus that is morphologically identical to the sinus lined by PDGFRa-positive cells, and weak signals were detected in villous visceral yolk sac endoderm. This staining pattern is consistent with previous immunohistochemical studies on the expression of calbindin-D9k protein. We concluded that the probe for our cloned mouse homologue of calbin-din-D9k can detect the mRNA of mouse calbindin-D9k and serve as another histological marker for the IPY.
Impaired IPY Development in the Pdgfraph/Pdgfraph Mouse
To investigate whether PDGFRa-expression is functionally required for IPY development, we attempted to examine the placentas of the Pdgfraph/Pdgfraph homozygous mutants that lack the Pdgfra gene . As mentioned above, we introduced a DBA/2 or BALB/c genetic background into C57BL/6S-Pdgfrapl’/ + mutants, to improve the chances of obtaining Pdgfraph/Pdgfraph embryos that would survive beyond 13.5 dpc. In this study, 4 viable Pdgfraph/Pdgfraph embryos, which represented 13.5, 14.5, 15.5, and 17.5 dpc, were recovered. buy prednisone
FIG. 4. Placentas from Pdgfraph/Pdgfraph embryos and wild-type littermates. A, B) Placenta of a 14.5-dpc wild-type embryo that is a litter mate of С and D. C, D) Placenta of a 14.5-dpc PdgfraFh/PdgfraPh embryo obtained from BD-PdgfraFh mice. E, F) Placenta of a 17.5-dpc wild-type embryo that is a litter mate of G and H. G, H) Placenta of a 17.5-dpc Pdgfraph/Pdgfran embryo obtained from BB-Pdgfran mice. The left images are HE-stained specimens, and the right ones are the serial specimens of the left, stained by ISH for calbindin-D9k. Placentas of Pdgfraph/Pdgfraph embryos completely lack the IPY/sinus of Duval. Note that at the border of the visceral and parietal yolk sac in Pdgfraph/Pdgfraph placentas, there are calbindin-D9k-strong!y positive epithelial cells, which form villous epithelium similar to the columnar epithelium of a normal IPY (arrowhead in E). Scale bar, 100 (im.