Figure 6: Downregulation of the GCM1/syncytin-B pathway, and failure of fusion in the placenta of Bcl9l-deficient mice.
From: Identification of a link between Wnt/β-catenin signalling and the cell fusion pathway
(a) qRT–PCR analysis of trophoblast marker gene expression in the placentas of 4–6 concepti at different embryonic stages. Bars representing Gcm1 expression levels at E8.5 (dotted box) are magnified and shown above. ND, not detectable. SynB were not detectable in approximately half of the samples of wild-type and Bcl9l+/− and all of Bcl9l−/− at E8.5. Values were normalized by GAPDH expression level and indicated as mean±s.e.m. *P<0.05; **P<0.005 (wild-type versus Bcl9l−/−). Statistical tests were performed using the two-tailed Welch's t-test. Results without any indication are not statistically significant. Open bars represent wild-type, grey bars, Bcl9l+/− and black bars represent Bcl9l−/−. (b–f) Electron microscopic analysis of chorionic trophoblasts from E8.5 (b,c), E9.5 (d) and E10.5 (e,f) placentas. (b,f) Bcl9l−/−. (c–e) Bcl9l+/−. Note elongation and fusion of chorionic trophoblast cells in Bcl9l+/− placenta at E9.5 (d), whereas basal chorionic trophoblast cells remain unfused and undifferentiated in Bcl9l−/− placenta at E10.5 (f). Open arrowheads, nuclei of ST-II; B-CT, basal chorionic trophoblast; ec, fetal capillary endothelial cell; fc; fetal red blood cell; ms, maternal blood sinusoid; stgc, sinusoidal trophoblast giant cell; ST-P, ST precursor cells. Scale bars, (b–f) 5 μm.
